To "cut" or remove a server from an assigned schedule, first go to "server mode".
Select the server by pressing them, and then press the "Relieve" button to remove them from their tables.
Select the "Sched" tab at the top of the server list at the left.
Find the server in the current shift schedule, and swipe from right to left, revealing a delete button.
Press the delete button and the server is removed from the schedule and from the Active tab.