This feature requires an active PBX interface.
Path: Front Office > PBX > Guest
1. Search the guest by entering their name in Guest Information or select their room number from the drop-down.

The other tabs - Group, Arrival, and Departure - are only for guest search. Search for a guest who is part of a group or search by arrival or departure dates. Once you choose the guest, it will go back to the first tab Guest.