A warm planDisney welcome to you, Lynn. We're so glad you found us to ask this question. Oh dear, I'm so sorry to hear that you are in this situation. I'm happy to share some information and suggestions with you.
A valid theme park ticket and theme park reservation are required to enter both Disneyland Park and Disney California Adventure Park. I suggest keeping a watchful eye on the
Theme Park Reservation Availability calendar. Guests' plans can change and you may see a reservation become available for your visit date. I've used this strategy in the past and I have been very lucky and able to find a reservation for my visit date, however, there is no guarantee that a reservation will become available.
If your niece has a
Park Hopper ticket and a reservation opens for the opposite park that you are starting in, you can still make the reservation and once park hopping begins at 11:00 a.m., you will be able to be in the same park together. Or you can start your day together a little later, as once park hopping starts, you can enter either theme park. Again, you can always keep an eye on the reservation calendar to see if a reservation opens up for your starting park and quickly make a modification.
Lastly, if you aren't able to get a reservation, you can always look for a future date to reschedule your magical visit. If you aren't able to find a date that works before the ticket expiration date, there is some flexibility to apply its value toward the purchase of a new ticket.
The value of a wholly unused and expired ticket (excluding special event tickets) can be applied toward the purchase of a new theme park ticket as long as the purchase price of the new ticket is equal to or greater than the amount paid for the original ticket.
Lynn, I'm really sorry and wish I had better news to share with you. I hope that the information is still helpful. Most of all, I hope that a reservation opens up for your niece and that you are able to make your magical visit as planned. I'll be sending an extra dose of pixie dust your way.
Michelle