Layton ServiceDesk - General Settings - Default Closed Periods
From Layton Support
This option allows you to specify the days that the ServiceDesk will not be working. These will be Public or Bank Holidays or specific days that the ServiceDesk will be closed. This ensures that Request escalation does not occur over closed periods. Weekends should not be specified here as they are more efficiently accounted for in the Working Hours section below.
To create closed periods go to Administration > General Settings > Closed Periods and click the Add icon. A new Closed Period pop up dialog will appear with a blank start and end date/time. Enter the start and end date/time and save.