The term "Rekey" means change the internal workings of a door lock so the old key cut no longer opens the lock. The lock is reset to work with a different key cut. The door locks and knobs are not replaced, only the internal mechanisms. Rekeying your locks is a cost effective way to change the keys to your home or rental property without replacing hardware. There are many situations where rekeying is recommened below are some of the most common.