If the call is to a user, and they do not answer, you can set a callback. When a callback is set, when the other user next uses their phone or ends their current call, the system will call you and when you answer, automatically makes another call to the user.
1.While the call is still ringing or if you hear busy. Press Callback.
2.End your call attempt by replacing the handset or pressing Drop.
If you have a callback set, you can cancel it using the following process:
1.Press Feature #2.