You can easily remove shifts from a schedule on days they are not needed. Doing so keeps the schedule current, and prevents people from being scheduled when they aren't needed.

1. From the open schedule, click on the shift so that it is highlighted.
2. Click on the Schedule menu at the top of the window and select "Delete Shift..."

NOTE: Following the above steps will only remove the shift from this particular date - not all instances of the shift, if it is repeating.