Return tickets security?

We have an issue where an order is placed and users who don't have access to the performance yet, are able to go in and return the tickets even though they are part of the security group that technically doesn't have access to this certain season yet. 

Is there a way to prevent this from happening?  This is an advance period of sale for our donors and some of them call the box office to change their tickets and even though these operators don't have access to the season yet they can go in and return the tickets. We don't want this to be able to happen.

Thanks!

Amy