Hello, Colleen!
Welcome back to planDisney! Thank you so much for trusting us to answer your questions, and we are so honored to be on your PLANNING TEAM!
I am so sorry your sister will not be able to join you for your upcoming trip to the Disneyland Resort! Please let her know that Mickey Mouse and her pals will be so sad, but we totally understand when schedules change. However, we can't wait to see her hopefully very soon!
I want to let you know that
Disneyland Theme Park Tickets are nonrefundable. HOWEVER, all hope is not lost! If you are not able to make it back to the HAPPIEST PLACE ON EARTH before this theme park ticket expires, you can apply the funds used to purchase your sister's ticket for a new ticket purchase equal to or greater than the amount paid for the original ticket.
Another idea would be to invite another family member or friend to come with you!!! You could then reassign the ticket to a new person, and I promise the person you invited would be SOOOOO excited! (I KNOW I would!)
I hope this information is helpful to you. Please know if you need anything else, we are here to help in any way! Thanks so much for everything!
Have a MAGICAL day!
Wes