Iwatsu ENTERPROSE-CS Owner's Manual page 268

 Press the Speaker key SPKR
To cancel Message Waiting:
 Press the Speaker key SPKR
 Wait for the dial tone
 Press the Message Waiting Control key MSG CTRL
 Dial the guest room extension number
 Press the Release key RLS to cancel a message
 Wait for a confirmation tone
 Press the Speaker key SPKR
To reply to a message from a guest room:
 Lift the receiver
 Wait for dial tone
 Dial the extension number for the operator or message center
HOSPITALITY FEATURES USER GUIDE - 250