Removing a special activity from a list of constituents

For some reason, the utility for managing special activities doesn't have an option to remove the activity altogether from the list. I was trying to do it in SSMS, but I can't find where the connection between lists and the constituents on them lives. Is there a way to join two (or more) tables to remove an activity from just the people on the three lists it was accidentally applied to? We can live with it if not (it's a matter of the regular party being added instead of the VIP party, so we can just add the VIP party and ignore the regular).

Thanks!
Anne Robichaux
The Historic New Orleans Collection