Click on the user and select Deactivate User. This will not delete the user. It will only temporarily disable the user access. The lock will now show the user as Disabled. To re-enable the user, click on the user and select Reactivate User. The user will then be able to unlock the lock.
Only Temporary users can have scheduled access with time of day and beginning and end dates. Their access can be changed even after the end date. You have to manually delete them.