Welcome to planDisney, Mary! Thanks so much for coming to us with your question today.
If you have a
date-based ticket that you did not use on the date you selected and you also did not change your use date in the
My Disney Experience app before it passed, I recommend that you
call the hotline for Existing Tickets as soon as possible. The window for use for date-based tickets can be changed before they are used, but they typically expire if the use window comes and goes without someone using the ticket. That's why it's important that you call the ticket hotline as soon as possible. They will be able to assess your ticket type and tell you what your options are going forward.
In the event that you do not have a date-based ticket and your ticket type requires a
park reservation, all you need to do is change the date of your reservation and you'll be able to use it at a future time. Park reservations are flexible and you can modify them at your leisure!
I hope this answers your question, Mary, and I hope we see you back here soon with more questions about a future vacation!
Jessica