Key replacement refers to the process of obtaining a new key when the original is lost, damaged, or no longer functional. This can involve cutting a new key based on a code or template, or rekeying a lock, which changes the internal mechanism so that the old key will no longer work. In many cases, key replacement services are offered by locksmiths or hardware stores. Some modern locks, such as those found in smart home systems, may allow for digital key replacement through an app, providing a convenient alternative to traditional methods.