Hey there, Melissa. Welcome to planDisney. Your trip is just days away, so let's get your question answered!
Currently, there is no way for you to modify your
theme park reservation without first canceling your current theme park ticket reservation. If reservations are full for that day and you cancel, you will lose out on your reservation. This is why I always tell my friends to double and triple-check the
Theme Park Reservation Availability Calendar before they confirm their reservation cancellation to be sure that they can rebook for the day and park they want.
I just took a look at the Availability Calendar and unfortunately it does look like that date is completely booked at the time of writing this. I do recommend checking the calendar often because the calendar is fluid and will change as Guests book and cancel reservations. I will share that I have had success with getting a last-minute reservation for a day that was previously full late on the night before, so that may be worth checking the night before.
As you count down the last days before your arrival, my tip is to download the
Disneyland app now if you haven't already. Log into your Disney account and make sure your tickets are linked and ready. I also recommend you add a card to your profile as this will make mobile food ordering super easy and convenient!
Melissa, I hope you have the most magical visit to Disneyland Resort. See you real soon!
Carrie