Account for existing keys
Ask the owner or agent which keys exist and who may hold copies. Include entrance doors, garages, gates and shared spaces.
Discuss changes with the owner
If you rent, check your agreement and obtain any needed permission before replacing locks. Keep the agreed access arrangements clear.
Choose a suitable solution
A locksmith can discuss whether the existing lock is serviceable and which replacement or rekeying options may suit it. Request a quote before work starts.