Hi there, William!
William, it sounds like you have successfully navigated the ins and outs of the
Disney Park Pass system in advance of your trip to the Most Magical Place on Earth!
If you happen to wake up and decide that today feels more of like an
EPCOT day, instead of a
Magic Kingdom day, you are able to change your Disney Park Pass system reservation, as long as there is availability in the park that you wish to visit.
William, you can easily check if same-day reservations are available on the
availability calendar. Please note that as you are not able to modify your reservation, you must cancel your existing reservation before you can book another.
So, William, while you can change your park the day of, I would recommend that you do so sparingly. You would not want to be in a position where you are canceling your existing reservation while your newly desired theme park books up. Please note that if you have scanned into a theme park for the day, you will not be able to make an additional reservation for that same day, even if you have left the park.
I hope that this answered your question, William! It is always a pleasure to talk to you so please come back if we can help answer any other questions about your upcoming trip to Walt Disney World Resort.
See you real soon!
Sarah B.