Deleting a service will not only remove it from the schedule, it will also remove the service from a volunteer's scheduling history, allowing them more of a chance to serve in the future. Once a service is deleted, it cannot easily be restored.
To delete a service, first open the schedule in the Schedules pane of MSP.
1. Click on the date of the service in the calendar view on the left
2. Click on the service to select it
3. In the Schedule menu, select "Delete Service..."
Now the service will no longer appear on that day in the schedule!