Hey Howdy Hey Sandra and welcome to planDisney!
What a nice surprise finding that extra ticket to use for your upcoming vacation! I am sorry you were not able to experience Mickey's Verry Merry Christmas Party last year. It does sound like you have an extra opportunity for more Magical time in the parks for your upcoming vacation. To answer your question on your ticket options, it depends on how you have booked your upcoming vacation. Let's go over a few scenarios and see what we can come up with.
The biggest thing that would impact your ability to modify your vacation is if you booked your trip as a vacation package or separately. When booking a
vacation package with Disney, this usually involves a stay at a Disney Resort Collection hotel and theme park tickets at minimum, these are typically very flexible. You are able to change any part of your vacation 30 days or more from your date of arrival without penalty. This would include modifying your park tickets. If you wanted to downgrade your current package to 3 days and then use the extra day from last year you are more than welcome to.
Modifications can typically be made online in your
My Disney Experience account. Once you log in, you should see your reservation on the home screen and a blue hyperlink to "Modify Reservation" to the right of it. You can go right to the theme park tickets and update to 3 days. You will be asked to verify the change and then will give you the new total due 30 days before your date of arrival. Any changes made after your final payment due date are still possible but do come with a fee of $50.00 (prices subject to change without notice).
If you did book your vacation with separate parts, meaning that you purchased the tickets separately from your hotel accommodations, this is very different. Disney has a firm policy that all tickets are non-refundable. So your 4 day park ticket now becomes 5 with your new ticket with a park hopper! I would think of this as a grand opportunity to slow down, experience all that you want to and feel free to do anything again with your extra time in the parks!
Depending on how you booked your upcoming vacation Sandra, here you have your options. I hope this information helps to clear up where to go from here and I wish for a Magical vacation experience for you and your husband in November. If you have any other questions, please feel free to let us know, we are always happy to help!
To Infinity and Beyond,
Nick