### Answer --- If SMS options aren't showing for your Twilio number after purchase, it's likely because SMS capabilities haven't been enabled yet [(1) ]() . For Retell Twilio numbers, enabling SMS requires going through an application and approval process that includes : 1. Getting approved for a business profile (free) 2. Getting approved for the brand based on business profile ($4 one-time fee for low-volume or $45 for standard) 3. Getting approved for an SMS campaign ($15 one-time fee) This entire application process can take around 2-3 weeks, sometimes longer, as it's a manual review process on the telephony provider side . You'll be notified via email when the application is approved or rejected . If you're bringing your own Twilio number that already has SMS enabled, you need to integrate it by : 1. Navigate to your phone number settings in the Retell dashboard 2. Click "Setup SMS Function" under Advanced Add-Ons 3. Provide your Twilio Account SID and Twilio Auth Token (found in your Twilio Console under Account Info) Make sure your Twilio number already has SMS capabilities enabled and is compliant with SMS regulations before integration . If your application has been pending for an extended period, reach out to support and they can help escalate .

​ To learn more, see the sources I considered: [[1] Send & receive SMS](https://docs.retellai.com/deploy/enable-sms) ​

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

### Answer To start the SMS application process for your Retell Twilio number [(1) ]() : 1. Go to your Retell dashboard 2. Click on phone numbers [(2) ]() 3. Select the Twilio number you purchased 4. Click on SMS [(1) ]() [(2) ]() From there, you'll follow these steps [(1) ]() : Step 1: Get approved for a business profile You can reuse an existing business profile or create a new one . You'll need to fill out accurate business information including business type, industry, EIN (or select sole proprietorship if you don't have one) , business registration number, website, and physical address [(1) ]() [(2) ]() . Step 2: Select a brand type and get approved [(1) ]() Choose between: - **Low-volume**: $4 one-time fee, send fewer than 6,000 message segments per day to the US - **Standard**: $45 one-time fee, SMS limit between 6,000 and 400,000 message segments per day to the US Step 3: Get approved for an SMS campaign Fill out the use case and sample messages you intend to send . Be detailed and honest, as your actual traffic must match the sample messages or your number might be suspended [(1) ]() [(2) ]() . The entire process takes around 2-3 weeks for approval [(1) ]() .

​ To learn more, see the sources I considered: [[1] Send & receive SMS](https://docs.retellai.com/deploy/enable-sms) [[2] A2P Setup ultra guide | Enable SMS for Your Retell Agent]() ​

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

### Answer Based on your situation, here's why the SMS option might not be showing: Only Retell Twilio numbers support SMS [(1) ]() . If you're using a number that shows as "Custom telephony" in your dashboard, the SMS option won't appear [(2) ]() [(3) ]() . To check your number type: 1. Go to your Retell dashboard 2. Click on phone numbers 3. Select your purchased number 4. Look at the "phone_number_type" field [(4) ]() If it shows "custom" instead of "retell-twilio", that's why SMS options aren't visible [(2) ]() [(3) ]() . If you purchased the number directly from Retell: The SMS option should appear under the number settings. If it doesn't, the number might not be a Retell Twilio number [(1) ]() . If you brought your own Twilio number via SIP trunking: SMS won't work through Retell's dashboard [(5) ]() [(3) ]() . As one support member explained: "sms only works with retell twilio numbers as of right now" and "since you own the number through twilio, there's no way for retell to send the message" [(3) ]() . Your options: - Purchase a new number directly from Retell (not through SIP trunking) to get SMS capabilities [(1) ]() - Use your existing Twilio number for voice

only and handle SMS through your own Twilio automation [(5) ]() [(3) ]() Can you confirm whether your number shows as "retell-twilio" or "custom" in the phone number settings?

​ To learn more, see the sources I considered: [[1] Send & receive SMS](https://docs.retellai.com/deploy/enable-sms) [[2] Business Profile Approval for SMS Campaign Submission](https://discord.com/channels/1186424376300679209/1397608648657604658) [[3] Setup SMS Function Not Saving for Twilio Integration](https://discord.com/channels/1186424376300679209/1446220160213061865) [[4] Get Phone Number](https://docs.retellai.com/api-references/get-phone-number) [[5] Discord message from @dumpfile on 2025-12-12](https://discord.com/channels/1186424376300679209/1186462578310910112/1448883478589472800) ​

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

### Answer If your number shows "Provider: Twilio", you need to check whether it's a Retell Twilio number or an imported Twilio number via SIP trunking [(1) ]() [(2) ]() . To determine this, check the

phone_number_type

field: - If it shows

"retell-twilio"

, SMS should be available [(3) ]() [(4) ]() - If it shows

"custom"

, this is an imported SIP trunk number and SMS won't work through Retell's dashboard [(1) ]() [(2) ]() For Retell Twilio numbers (

retell-twilio

) : The SMS option should appear in your phone number settings [(3) ]() . If you purchased the number directly from Retell and don't see the SMS option, there may be a dashboard display issue. For imported Twilio numbers (

custom

) : SMS functionality is not supported through Retell for numbers imported via SIP trunking [(1) ]() [(2) ]() . You would need to handle SMS separately through your own Twilio account. Alternative solution: If you already have a Twilio number with SMS capabilities enabled, you can integrate it by [(3) ]() : 1. Navigate to your phone number settings in the Retell dashboard 2. Click "Setup SMS Function" under Advanced Add-Ons 3. Provide your Twilio Account SID and Auth Token This integration method requires that your Twilio number already has SMS capabilities enabled and is compliant with SMS regulations . Can you check what the exact `phone_num

ber_type` value shows for your number in the dashboard or via the API? [(4) ]()

​ To learn more, see the sources I considered: [[1] Import Phone Number](https://docs.retellai.com/api-references/import-phone-number) [[2] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) [[3] Send & receive SMS](https://docs.retellai.com/deploy/enable-sms) [[4] Get Phone Number](https://docs.retellai.com/api-references/get-phone-number) ​

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

### Answer ### Answer To transfer a call from your AI agent to another agent (human or AI) , use the Transfer Call feature [(1) ]() . Setup Steps: 1. Add Transfer Call Tool Click "+ Add" in the tools section and select "Transfer Call" from the dropdown menu . 2. Setup Transfer Target Set the transfer number to either : - A number in e.164 format (e.g., +12345678900) - A SIP URI in the format

sip:username@domain

(e.g.,

sip:user@retellai.com

) - A dynamic variable that gets substituted at runtime If needed, set the transfer number extension (must be 0-9, '*', '#', e.g., 123#) . 3. Update the Prompt Add instructions to your agent's prompt about when to transfer . For example: "If the user is angry or frustrated, use the transfer_call tool to transfer the conversation to a human agent." 4. Configure Transfer Type Choose between : - **Cold transfer**: The call is transferred to a destination number and that's it - **Warm transfer**: After the call is transferred, the AI agent can detect if the other side is human, leave private messages not heard by the user, do a three-way introduce, etc. *5. Configure Caller ID (Optional) * You can configure which caller ID shows up to the transfer destination : - **Retell Agent's number**: The transfer destination will see the Retell agent's number - **User's Number**: The transfer destination will see the number of the user (requires telephony provider support for caller ID override) *6. Configure Warm Transfer Settings (if using warm transfer) * For warm transfers, you can configure : - **On-hold music**: Audio played to the caller while on hold (default is ringtone) - **Navigate IVR**: Prompt to help navigate if the transfer target is an IVR system - **Enable human detection**: Agent checks if a human is present after t

he transfer target answers - **Auto-greet**: Agent immediately says "Hello" when transfer target picks up - **Agent detection timeout**: Maximum time to wait to determine if transfer target is human (default 30 seconds) - **Whisper message (optional) **: Message spoken privately to the transfer target before connecting them to the original caller [(1) ]() [(2) ]() - **Three-way message (optional) **: Message spoken to both the transfer target and original caller once connection is established *7. Add Custom SIP Headers (Optional) * Add custom SIP headers for outbound calls that are forwarded to your SIP provider on the SIP INVITE [(1) ]() . All header names must start with

X-

.

​ To learn more, see the sources I considered: [[1] Transfer call](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[2] Warm Transfer vs Cold Transfer - The AI Advantage in Call Centers | Retell AI](https://www.retellai.com/blog/effortless-handoffs-with-retell-ais-warm-transfer-feature) ​

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

### Answer The Agent Transfer Node (also called Agent Swap) enables you to transfer the conversation from one AI agent to another AI agent within Retell [(1) ]() . This is different from transferring to a human agent via phone. Why Use Agent Transfer Instead of Call Transfer? Agent Transfer offers significant advantages over traditional call transfer : - **Lower Latency**: Near-instant transition between agents - **Better Reliability**: No need to create a new phone call, avoiding potential telephony failures - **No Handoff Message Needed**: The destination agent has access to the full conversation history, eliminating repeated customer questions - **No Separate Numbers for Agents**: Agents receiving transfers don't need their own phone numbers Setup Steps: 1. **Add Agent Transfer Node**: Select "Agent Transfer" from the 'Add New Node' menu 2. Configure Details : - **Transfer agent**: The ID and version of a specific agent to transfer to (you can select the latest version as well) - **Speak during execution and messages**: Whether the agent should speak something while performing the transfer - **Post call analysis setting**: Choose to extract dynamic variables for only the transferred agent, or both agents 3. **Test and Debug**: You can test agent transfer both in web call and playground Transfer Settings Behavior: The following settings of the first agent will be used throughout the call : - optInSignedUrl - optOutSensitiveDataStorage - webHookUrl All other settings (language, voice, voiceModel) will reflect the currently active agent .

​ To learn more, see the sources I considered: [[1] Agent Transfer Node](https://docs.retellai.com/build/conversation-flow/transfer-agent-node) ​

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