Once a division schedule has been created and saved, when viewing the division, at the bottomn of the page, you have the option to lock the division. If the division is already locked, you have the option to unlock it.

The effect of locking a division is to prevent any changes to the scheduled games other than official assignment changes, game status, or comments. This means that the date, time, venue, or teams of any game in thee division's schedule cannot be changed without unlocking the division.