### Answer I don't have specific information about call forwarding costs in the available sources. The documentation covers call transfer features and SIP trunking integration, but doesn't detail the pricing structure for call forwarding specifically [(1) ]() [(2) ]() . For detailed pricing information about call forwarding and other telephony costs, I'd recommend checking out these potentially useful sources: - [Connect Retell voice agents to custom telephony]() - [Call transfer node in conversation flow]() Would you like a general answer based on my knowledge instead, or would you prefer to contact Retell AI directly for specific pricing details?

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

​ To learn more, see the sources I considered: [[1] Connect Retell voice agents to custom telephony](https://docs.retellai.com/deploy/custom-telephony) [[2] Call transfer node in conversation flow](https://docs.retellai.com/build/conversation-flow/call-transfer-node) ​

### Answer I don't have specific pricing information for call transfers in the available sources. The documentation covers the technical implementation of call transfer features, including cold transfer, warm transfer, and agentic warm transfer [(1) ]() , but doesn't detail the cost structure for transfers. For your setup where you want to transfer from Retell AI to a third-party dialer, the transfer functionality is supported through the Call Transfer tool . You can transfer to a phone number in E.164 format or a SIP URI . However, the actual cost would depend on: - Your telephony provider's rates (Twilio, Telnyx, Vonage, etc.) - Whether you're using Retell numbers or imported numbers via SIP trunking [(2) ]() - The duration of the transferred call - Any additional charges from your third-party dialer system The 16 cents per minute you mentioned would typically come from your telephony provider's pricing, not Retell AI itself. I'd recommend: 1. Checking your telephony provider's transfer/forwarding rates 2. Reviewing your third-party dialer's inbound call costs 3. Contacting Retell AI support for specific pricing details about their platform fees Would you like more information about the technical setup for call transfers, or would you prefer to contact Retell AI directly for pricing specifics?

​ To learn more, see the sources I considered: [[1] Transfer call tool (single & multi-prompt agents)](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[2] Connect Retell voice agents to custom telephony](https://docs.retellai.com/deploy/custom-telephony) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer It depends on which transfer type you choose [(1) ]() : **Cold Transfer**: Retell drops off immediately when the call is handed off . The call goes straight to the destination and your agent disconnects right away . **Warm Transfer**: Retell stays on the bridge during the queue and waits . The agent can wait for a real person to speak, play a private message only the destination hears, or do a quick three-way introduction before connecting your caller . You can configure settings like "Internal queue or hold system" to handle scenarios where the destination queues calls - the agent then waits until a real person starts speaking before it debriefs, within the "Wait Time for Agent Answer" you set . **Agentic Warm Transfer**: A second AI agent (the transfer agent) handles the screening while your caller waits on hold . Once the transfer agent bridges, your caller and the destination are connected directly and every AI drops off the call . For your flow (Retell → IVR → Agent can't handle → Transfer to third party → Third Party accepts) , if you use: - **Cold transfer**: Retell closes the bridge immediately upon transfer - **Warm transfer**: Retell stays connected during the queue until the third party accepts, then you can choose whether to drop off or do a three-way handoff The warm transfer settings let you control exactly when Retell disconnects through options like "Three-Way Debrief Message" and connection timing .

​ To learn more, see the sources I considered: [[1] Transfer call tool (single & multi-prompt agents)](https://docs.retellai.com/build/single-multi-prompt/transfer-call) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer I don't have specific information about Retell AI's billing structure for warm transfers in the available sources. The documentation covers the technical functionality of warm transfers, including how the agent stays on the line and waits for a real person to answer [(1) ]() , but doesn't detail the pricing or billing mechanics during the transfer process. For warm transfers, here's what happens technically : **During the transfer**: Your caller hears on-hold music while the destination rings . The agent waits until a real person starts speaking (within the "Wait Time for Agent Answer" you configure) . **When connected**: The agent can deliver a whisper debrief message privately to the destination (caller can't hear it) , or a three-way debrief message to both parties . However, regarding your specific billing question (whether you'd be charged for the full 8 minutes - 5 minutes hold + 3 minutes staff call) , I don't have that information in the sources. Billing would likely depend on: - Your telephony provider's rates (not Retell AI's platform fees) - How your SIP trunk or phone number provider charges for call duration - Whether charges apply for the entire bridge duration or just active conversation time I'd recommend checking out these potentially useful sources: - [Transfer call tool (single & multi-prompt agents) ]() - [Connect Retell voice agents to custom telephony]() Would you like a general answer based on my knowledge instead, or would you prefer to contact Retell AI directly for specific billing details?

​ To learn more, see the sources I considered: [[1] Transfer call tool (single & multi-prompt agents)](https://docs.retellai.com/build/single-multi-prompt/transfer-call) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Yes, with cold transfer the caller remains connected to your dialler without being disconnected [(1) ]() . Here's what happens: With cold transfer, the call goes straight to the destination and your Retell agent drops off right away . The handoff is seamless - the caller is transferred directly to your dialler number and stays connected throughout . The caller won't experience a disconnection. Cold transfer works like transferring a call and hanging up - the Retell agent exits the call, but the caller's connection continues to the new destination (your dialler) . This is different from warm transfer where the Retell agent stays on the line after dialing the destination . With cold transfer, Retell disconnects immediately upon handoff, but the caller's connection to your dialler is maintained . Cold transfer works for Retell numbers and imported numbers [(1) ]() [(2) ]() . The transfer happens after the agent finishes speaking the content in that response [(1) ]() .

​ To learn more, see the sources I considered: [[1] Transfer call tool (single & multi-prompt agents)](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[2] Connect Retell voice agents to custom telephony](https://docs.retellai.com/deploy/custom-telephony) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

Thanks for the follow-up, @Ciaran. I'll get back to you soon.

### Answer I don't have specific pricing information about cold transfer costs in the available sources. The documentation covers the technical functionality of cold transfers [(1) ]() , but doesn't detail the cost structure. What I can confirm technically: With cold transfer, the call goes straight to the destination and your Retell agent drops off right away . The caller remains connected to your third-party dialler without being disconnected . However, regarding costs, this would depend on: - Your telephony provider's rates (Twilio, Telnyx, Vonage, etc.) [(2) ]() [(3) ]() - Whether you're using Retell numbers or imported numbers via SIP trunking [(2) ]() - How your provider charges for call transfers/forwarding - Any charges from your third-party dialler for receiving the inbound call The key point: While Retell disconnects from the call during a cold transfer [(1) ]() , you're still routing a call through your telephony infrastructure. Your telephony provider may charge for: - The initial call leg (caller to Retell) - The transfer/forwarding action itself - The ongoing call (caller to your dialler) I'd recommend checking your telephony provider's specific pricing for call transfers and forwarding. Would you like a general answer based on my knowledge instead, or would you prefer to contact Retell AI directly for specific pricing details?

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer The "Transfer call cannot be completed, probably don't have the permission to perform the transfer" error typically indicates a permissions or configuration issue [(1) ]() . Here's how to troubleshoot: For Single/Multi-Prompt Agents : 1. Verify you've added the

transfer_call

function to your agent's function list 2. Check that your agent's prompt clearly defines transfer conditions 3. Ensure the

transfer_call

function description is specific and unambiguous For Conversation Flow Agents : 1. Verify you have a transfer node in your conversation flow 2. Ensure the transfer node is properly connected to other nodes 3. Check that transition conditions are correctly set up 4. Confirm the transfer destination is correctly configured General Checks : - Call transfer is only supported for phone calls, not web calls - If the call transfer is triggered but failed, check for telephony issues in the SIP connection log available in your call logs **Permissions Issue**: If you're a developer in the workspace, there was a recent issue where developers couldn't test calls due to insufficient permissions [(2) ]() . The solution was to either have the workspace admin grant admin access or wait for the team to fix the permission issue (which has been resolved) . Check your workspace permissions under Settings → API Keys to ensure your role has the necessary access [(3) ]() .

​ To learn more, see the sources I considered: [[1] Debug call transfer failure](https://docs.retellai.com/reliability/call-performance) [[2] Insufficient permissions](https://discord.com/channels/1186424376300679209/1428849621022670938) [[3] Manage API keys and permission scopes](https://docs.retellai.com/accounts/manage-api-keys) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer For a Conversation Flow cold transfer using "User's Number" as the caller ID, the permission error you're seeing is likely because caller ID override isn't supported by your telephony provider [(1) ]() [(2) ]() . Here's what's happening: Caller ID Override Requirements : - For cold transfer, it uses SIP REFER, and it's up to the telephony provider to support caller id override for SIP REFER - If caller id override is not supported, the transfer would fail Provider-Specific Support : - Retell Twilio numbers support showing user's number on both warm and cold transfer - Retell Telnyx numbers only support this when using SIP REFER via cold transfer **Solution**: Try changing your cold transfer configuration: 1. Switch Displayed Caller ID from "User's Number" to "**Retell Agent's number**" [(1) ]() , or 2. If you must show the user's number, verify your telephony provider supports caller ID override for SIP REFER [(1) ]() [(2) ]() The cold transfer mode setting has two options [(1) ]() : - **SIP INVITE**: Default method, allows caller ID choice - **SIP REFER**: Requires provider support for caller ID override If you're using imported numbers via custom telephony, confirm with your SIP trunk provider (Twilio, Telnyx, Vonage, etc.) whether they support caller ID override for cold transfers [(3) ]() .

​ To learn more, see the sources I considered: [[1] Call transfer node in conversation flow](https://docs.retellai.com/build/conversation-flow/call-transfer-node) [[2] Transfer call tool (single & multi-prompt agents)](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[3] AI in SIP Calling & Telephony Solutions | Retell AI](https://www.retellai.com/blog/integrating-ai-with-sip-trunking-and-modern-telephony) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Yes, with cold transfer the Retell call ends immediately when the transfer happens [(1) ]() . The call goes straight to the destination and your agent drops off right away . This is exactly how cold transfer works - it's like transferring a call and hanging up . The Retell agent exits the call completely, while the caller's connection continues seamlessly to your destination number . So for your Conversation Flow setup with cold transfer to a static number, once the transfer executes, the Retell call will end and you'll no longer be charged for that call leg . The caller stays connected to your third-party dialler without experiencing any disconnection .

​ To learn more, see the sources I considered: [[1] Transfer call tool (single & multi-prompt agents)](https://docs.retellai.com/build/single-multi-prompt/transfer-call) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.