Resetting a Master Lock can vary depending on the model. For combination locks, you usually need to open it first. Oftentimes, resetting involves turning the shackle, pushing it down, and setting a new code using the dial or buttons. It's always a good idea to check the specific instructions for your lock model. Have you already unlocked your Master Lock, or are you facing any issues? I'd be happy to guide you further if you need more help.