### Answer --- You can configure the caller ID setting in the Transfer Call Tool to show the user's number instead of the Retell agent's number. [(1) ]() In your Transfer Call Tool settings, look for "Configure Caller ID (Optional) " and select "User's Number" — the transfer destination will then see the number of the original caller. Important limitations to be aware of: - The telephony provider must support caller ID override for this to work. - For warm transfers, Retell uses SIP DIAL and sets the

from

and

P-Asserted-Identity

headers to the user's number. - For cold transfers, Retell uses SIP REFER, and caller ID override support depends on your telephony provider. - Retell Twilio numbers support showing the user's number on both warm and cold transfers. - Retell Telnyx numbers only support this when using SIP REFER via cold transfer. - If caller ID override is not supported by your provider, the transfer will fail. If you're experiencing transfer failures with "User's Number" selected, it may indicate your telephony provider doesn't fully support caller ID override for your transfer type. [(2) ]()

​ To learn more, see the sources I considered: [[1] Transfer call](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[2] Call transfer failures](https://community.retellai.com/t/call-transfer-failures/600) ​

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