Last call was a hospitality term for a warning to patrons of an establishment that closing time was imminent and everyone should make their final orders of the night.
In 2143, Ruby announced last call and asked what anyone wanted; A.G. Robinson ordered another drink. (ENT: "First Flight")
In 2375, before leaving USS Voyager's mess hall, Neelix announced last call, informing Harry Kim that there was "a bowl of soup in storage and I left the replicator online." (VOY: "The Disease")