Reschedule, optional days, and weekends

When I reschedule a program that has an optional day and/or a weekend, these days carry over when you reschedule. For example, if I decide to reschedule a Thursday to a Friday, the original Friday will be on Saturday, the optional day will be Sunday, and the empty Sunday will now be on Monday. Is there some way to avoid this? It makes rescheduling very messy. Thanks.