Master Locks are known for their security and reliability. However, if you've forgotten your combination or think it has been compromised, you're going to want to reset it. Doing this requires a specific process that you must follow if you ever hope to be able to reuse the lock. It's a good idea to reset your Master Lock when changing locations or uses. For instance, if you used it on your school locker but now want to use it as a bicycle lock, the combination should probably be reset.
Enter in the Master Lock's current combination. Open the lock by pulling the shackle up and turning 90 degrees counterclockwise.
Turn the combination dials to the new combination you want to use. Make note and memorize this new number.
Turn the shackle clockwise 180 degrees. The combination is now set. Lock the shackle and try out your new combination.