When performing a warm transfer inside the ECS Agent client that includes a 3-way conference where all parties are connected at the same time, the following steps should be followed:
- Click Consult
and contact the other Agent - Click Start Conference
to join all 3 parties together - Click Stop Conference
to put both calls on hold - Expand the Telephony Sessions to make both calls visible

- Click Retrieve
to take the caller off hold - Click Transfer
on the Agent call to complete the transfer
Please review this video that illustrates this sequence of steps.
