Call transfer to other agent through api

When an agent talking to a caller, and want to transfer to a specific agent. Best to use Quick Connect (Agent), and you can set the "Transfer to Agent" type flow to use. In the flow, you can check if the agent is in Available status to take the call, if not, you can drop this and cancel the transfer, send to a general queue, etc.

There is no API in the SDK to transfer a voice call, TransferContact is only for TASK channel.

You can use Stream API to initiate the transfer process (addConnection) here is a blog that talks about different kind of transfer and how you might be able to do it: https://aws.amazon.com/blogs/contact-center/making-cold-transfers-using-the-amazon-connect-streams-api/

Unfortunately, there is no API to transfer a voice contact to other agent.