In the event that you have accidentally given access to an unwelcome guest, or have used up all 285 available PIN codes, you can reset your lock via your Lock Info page in the Status tab (fourth icon on bottom tray) by selecting "Clear PIN list".

If the lock has been successfully reset, a pop-up will appear with the message "Resetting Lock for new codes", followed by a notification that your lock has been reset successfully.

Do note that once you reset, any previously generated PIN codes will become invalid. However, your Master PIN stays the same.