[header] How to reset a master lock [title] Open the lock using the old combination. [step] Once you open the lock, turn the shackle off to the side so that you can access the shackle hole. If you do not have the old combination to the lock, you will not be able to reset it. 
[substeps] If this is the first time you are using the lock, use the preset combination. This will be listed on the packaging material that came with the lock.