Change business access with a clear door list
Start with the openings people use rather than the number of keys on a ring. A front entrance, staff door, storeroom and yard gate can serve different groups. Decide which users should enter each area and who is responsible for approving access changes.
Master key systems can provide selected access groups on compatible hardware. They differ from keying every lock alike, which gives holders of the shared key the same access to those locks. A written door list makes that choice easier to discuss and maintain.
If a staff key has gone missing, identify every opening it operated. Changing one cylinder may leave another door on the old key. Where an authorized manager key should remain in use, include that requirement in the plan before work begins.
For electronic access, removing a user is only part of the review if they also held a physical key. Keep both items on the departure checklist. A log can show that a credential was used; it does not establish who carried it into the building.