Hey there Jacob and welcome to planDisney. Celebrating the winter holidays at Magic Kingdom Park, especially at
Mickey's Very Merry Christmas Party is something I look forward to every year. I just love the decorations, delicious holiday treats, and those little touches that remind me of the holidays growing up.
The best course of action is to contact a Cast Member with
Existing Tickets and see what they can do for you. They may be able to transfer your ticket to a different date if there is availability however, as of now, it looks like all party nights are sold out. Also, they may be able to credit you towards a future Mickey's Very Merry Christmas Party. If you can apply the ticket toward another date and there is a price difference you likely will be required to pay the difference.
Jacob, I hope this helps your wife and sister-in-law get to visit Magic Kingdom Park this year for the party to see
Mickey’s Once Upon a Christmastime Parade and
Minnie’s Wonderful Christmastime Fireworks Show. Please feel free to
write me back directly with any follow-up questions.
Enjoy making many Magical Memories.
~Jason