When you transfer a call, you can stay on the original call until the other person answers. This way, you can talk privately with the other person before you remove yourself from the call. If you don't want to talk, transfer the call before the other person answers.
You can also swap between both callers to consult with them individually before you remove yourself from the call.
From a call that is not on hold, do one of these actions:
Enter the other person's phone number.
(Optional) Wait until you hear the line ring or until the other person answers the call.
Press Transfer again.