Same thing really on our Nortell system.
➤ Record Your Greeting
Press 400 and sign into your mailbox.
Press 1 to select your external greeting (2 for internal, 3 for temporary)
Press 5 to record
Press # to end the recording
Press 2 to PLAY the greeting
To re-record, press 76 to delete, then 5 to record
Press 4 to return to your messages