By using the Whisper feature, a User can talk with an agent without being heard by the other person on the line. This is ideal for helping out with extra info, or coaching during training.
To Whisper into a call, you need granted permission and access to the Call Monitoring tab on your Admin Dashboard. Once there, you'll immediately see Live Calls:
Select the Whisper button associated with the call/User you want to whisper to.
While Whispering, you have the option to Join to the call, which means you are heard by everybody. To stop and exit the call, simply click the red Exit button. You can also choose to Listen only.
To use these features, you must turn ON Pro Dialing.
For Outbound calls, this feature can be turned on from Account Settings.
For Inbound calls, this feature can be turned on from Call Flows.