If you have to cancel a reservation give the restaurant as much advance notice as possible. A reservation is a verbal contract. Aside from the resulting lost revenue from your absence, you are also negatively impacting the front-of-house staff who are paid in proportion to sales. Your table will usually be held for at least fifteen minutes past the reservation time. If you don’t honor your reservation, the restaurant may not be able to rebook the table with a last minute walk-in. There may also be punitive consequences to chronic tardiness or a pattern of delinquencies. Most reservation systems are computerized and a “no-call, no-show”—as we call it—will be noted permanently on your profile. We may be less generous with you the next time you ask for a table.