When a schedule is no longer needed for your networks it can be deleted from the list. By removing a maintenance schedule, any network with the associated schedule takes on the settings of the System (Global) maintenance schedule (if one has been previously set).
To remove a scheduled maintenance window,
From the menu bar, select Tools -> System Administration.
Next, select Global - > Maintenance Windows.
Select the schedule (maintenance window), then click Remove. The confirmation window displays.
If okay, click Yes. Or, to cancel this action, click No.
The Maintenance Window updates with the selected item removed from the list.