I am being told by vapi, that warm transfer is not available with SIP. But when create a tool and choose the destination to be SIP I am able to select the transfer plan to be a warm transfer. Also the reason this came up in the first place is because when transferring, it does not say message or summary to operator. We even tried with non sip .. CAN ANYONE HELP

WARM transfers as of now only work with Twilio calls. The option is given out there. We need to add a filter if you select any other provider apart from Twilio. We shouldn't be showing you the property for the WARM transfer. For now, TLDR is WARM transfer only works with Twilio based number.

ok @Shubham Bajaj - so is there other workaround for this? We need some sort of message played before we make the transfer.. Maybe a conference call? blind-transfer-add-summary-to-sip-header?

Hey buddy, the warm transfer message works only if the telephony supports it. In case of Twilio, they have the API for it. But in case of other telephony when SIP is involved, they don't have the support for it and they have to build it on their end. Then they need to communicate it to us, that you need to send us a custom SIP header. It's more on your telephony side and less on our side