Suppose I plan a Waterpark on Wednesday and Epcot on Thursday. I plan my FP+ in Epcot. But then Wednesday comes and it is going to rain so I want to swap my water park day with my Epcot day. Doing so, I would loose all my Epcot FP+. Are people seeing that as a big deal? Or can you easily redo your schedule at the last moment and still get what you want?