You will be able to take that one day and upgrade it to another pass, no problem...make sure you do it before you enter the park and let them know what you want to upgrade it to (2, 3 day...etc)
They have a formula for figuring it out and prorating it, etc.
Save Up to 30% on Rooms at Walt Disney World!
Save up to 30% on rooms at select Disney Resorts Collection hotels when you stay 5 consecutive nights or longer in late summer and early fall. Plus, enjoy other savings for shorter stays.This offer is valid for stays most nights from August 1 to October 11, 2025.
CLICK HERE