​ To learn more, see the sources I considered: [[1] Issue with call transfer - not possible to transfer to second number if first one fails](https://discord.com/channels/1186424376300679209/1354765943334637634) [[2] Call Transfer Node](https://docs.retellai.com/build/conversation-flow/call-transfer-node) [[3] Transfer call](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[4] Debug call transfer failure](https://docs.retellai.com/reliability/call-performance) ​

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

### Answer --- There's a known limitation with sequential transfer attempts when using cold transfers. [(1) ]() When a cold transfer fails (e.g., no answer after timeout) , the underlying SIP REFER may still be active, causing subsequent transfer attempts to fail instantly. This is documented behavior where "the transfer is not stopped completely when the function call false is returned." Workarounds to consider: 1. Use Warm Transfer instead of Cold Transfer — Warm transfers give you more control over the process, including human detection and timeout handling. [(2) ]() [(3) ]() 2. Design your Conversation Flow — You can create multiple transfer nodes with different destination numbers and set up transition conditions based on transfer failure results. [(4) ]() 3. Use Dynamic Variables — Set the transfer number using a [dynamic variable](/build/dynamic-variables) that gets substituted at runtime, allowing you to programmatically control which number to try. [(2) ]() [(3) ]() Important note: For cold transfers specifically, there's a technical limitation where the first transfer attempt may block subsequent attempts during the same call session. [(1) ]() If fallback transfers are critical to your use case, warm transfer is the more reliable option. [(6) ]()