A contract between the hotel to provide a guest room on certain dates and rate and the guest who agrees to use the hotel on the specified dates at the agreed upon rate (and any other terms). If the guest breaches the reservation contract by being a no-show or failing to cancel on time, the hotel is owed damages. The usual term is the payment of one-night’s room rate (they shouldn’t charge you if they sell out. They also shouldn’t charge tax unless required by state or local law).