Longman Dictionary of Contemporary English
night porter
noun
EXAMPLES FROM CORPUS
▪ After arguing with the night porter for another ten minutes, they worked their way up floor by floor.
▪ Downstairs would be in darkness, so any light going on would attract the attention of the night porter.
▪ Scenario 1 Suppose the night porter has gone through to the kitchen to make a sandwich.
▪ The night porter used a passkey for those rooms that were empty or where no-one answered.
▪ The doors of the hotel were closed but the night porter appeared as soon as I rang the bell.
▪ This is a normal practice where, for instance, the night porter books in a guest after reception has closed.
▪ We think the night porter called them out, probably to make a few quid.
WordNet
night porter
n. a porter on duty during the night
Wikipedia
Night porter
A night porter is a porter who is on duty during the night. A hotel commonly has a night porter to attend to the needs of guests and other incidents during the night.
Traditionally a night porter might also be required to perform sundry maintenance and cleaning tasks such as polishing boots, emptying spittoons and laying fires.