A key-operated lock that can be programmed for use with one of a plurality of user keys without disassembling the lock or replacing the tumblers, that employs a programming key and an integral change tool to effect the lock programming. The lock can be configured to permit or to prevent use of the user key to program or reconfigure the lock. The lock is typically manually latched or bolted into a locked configuration. The integral change tooling simplifies the lock programming operation, and avoids the need for carrying a separate change tool.