Availability Tab

To enable the Availability tab, you must first navigate to Settings > Company Configuration > Configuration, and then select Availability Management checkbox icon.

The Availability tab on Login records allows you to enter the times in which individual logins will be available and unavailable to assign tickets to. The login will be displayed as unavailable or removed within the Assignee drop-down on the ticket screen in accordance with these entries.
availability tab

Add Working Day Times Enter the hours in which the login will be working on the HelpDesk.
add working times page
Add Holiday Enter dates of any scheduled holiday. The login will appear as (On Holiday) next to their name in the Assignee list to notify the ticket owner.
Unavailable To remove the login from the Assignee drop-down altogether, select the Unavailable tick box on the Login Details tab. The login will disappear from the Assignee drop-down until this is deselected.
unavailable checkbox