Hello Andrew!
How awesome- a surprise trip during December will be extra magical since the entire Resort will be decked out for the holidays! First, I want you to really make sure you won't want to utilize the Water Park Fun & More option, because it is a pretty good value. The water parks are heated year round and the addition of
DisneyQuest and the supercalifragilistic miniature golf courses can certainly add fun to your vacation. However, if you are sure you don't want to take advantage of these additional options and you have a package booked, you may be able to call
Disney Reservations and have them changed. Also, if you have a package booked, the trip is out far enough that you could cancel your reservation and re-book. However, if you have tickets without a package it is likely that you will not be able to change them. This is directly from the website:
"All tickets and options are nontransferable and nonrefundable and exclude activities/events separately priced."
I hope this is helpful and if you have more questions, come on back to the Disney Parks Moms Panel- we love to help!
See ya real soon!
Anne