Greetings from planDisney, Wendy! I'm so glad you've shared this question with us and I'll do my best to get you some helpful answers.
I'm so sorry to hear you've had a mixup with your plans! Please don't worry, this can happen to the best of us but I think we can figure out some solutions together. Generally, any standard multi-day theme park tickets purchased this year will be valid for 13 days after their first use or through January 12, 2025, whichever comes first (although you should verify the specific expiration date and terms of conditions associated with your tickets on the email confirmation you received). If you need even more time to make plans to visit Disneyland Resort, you may be able to apply the price you paid for your wholly unused tickets to a future ticket purchase of equal or greater value. This would potentially extend the window of time to use them, going forward.
Then, the next step would be to modify your theme park reservations. You can do this by logging in to your Disney account and selecting "My Plans" where you will see any currently held theme park reservations associated with the tickets linked to your account. You should see the button titled "Manage Reservation" which will give you the option to cancel your existing reservation and then you can rebook for a different date. I suggest reviewing the "Theme Park Reservation Availability Calendar to ensure there is availability before you begin this process.
If you also need to modify a hotel reservation or a dining reservation, you can go back to "My Plans" and follow the corresponding prompts to change or cancel a reservation directly from that page. Keep in mind that some changes may not be able to be made online, so you may wish to call Guest Services and speak with a Cast Member who can assist you with this process. I like to have all my confirmation numbers on hand when I call, so I can easily reference them when needed.
Wendy, I hope this puts you at ease knowing that the Disneyland Resort vacation of your dreams is still possible, with a few modifications! I hope you have the most delightful time and make lifelong memories at the 'Happiest Place on Earth!' There's never been a better time to celebrate the legacy of Disney storytelling, imagination, and discovery, as the Disney100 Celebration continues throughout the rest of this year. If we can help you with any other advice or recommendations, please come back and see us again here at planDisney.
Wishing you Wondrous Journeys,
Tishra