In-situ service involves bringing food and beverages to customers where they are located, rather than having customers come to a dining area. Common forms of in-situ service include tray service, where meals are served on trays to customers in places like hospitals or airplanes, and trolley service, where food and drinks are served from carts to customers at their seats or desks. Other examples are home delivery, lounge service, and room service in hotels. Room service can be centralized, with all orders processed from the main kitchen, decentralized with separate pantries on each floor, or mobile with pantries installed in service elevators.