Anyone ever done a last minute change?

[superrach]

My family has a Disneyland Good Neighbor package starting in 2 days on Monday, 6/25. We bought a Citypass with the hotel package and is curious if it's too late to change it to just Disneyland tickets? It would be a change from the Citypass to 5 day park hoppers. We are changing our minds about whether or not we want to go to Sea World and if we can even get these tickets changed.
Has anyone ever made a change like this?