Scheduling - reducing appointments

Hello, I'm a new user.  We have regular calendar schedules.   I'm trying to figure out how to reduce the number of appointments for one afternoon, or just one day.  (We have six calendars, three appointment types.)  So for example, on 8/16, I want to reduce the number of appointments for one calendar from 3 appointments per time slot to 1.   Does anyone have any suggestions?  Thank you.