Buzz wants you to use your Tier One FastPass+ for Alien Swirling SaucersThere is something that you need to keep in mind if you want to drop one FastPass+ reservation for another. Unless you’re checking for the Magic Kingdom, make sure that the attraction that you’re trying for is the same tier as the one that you would have to give up. Otherwise, you won’t be able to modify, and someone else will grab the hard to get reservation.