Anyone who has ever stayed at a hotel would be familiar with this kind of food service.
Guests staying at a hotel order for food and meals, and ask to be served in their rooms.
Smaller orders like snacks or dinner for one or beverages are brought to the guest's room in trays, while bigger orders like group lunches are brought down to the room by the waiter in food trolleys.
The guests can pay the bill to the waiter who has brought his food, or clears it later when he checks out from the hotel.