Hello, Donna!
Welcome to planDisney! I'm so sorry that your daughter isn't feeling well. That is no way to start off a holiday! I'll do my best to help you adjust your plans.
I'm unable to tell for sure from your question if you will be visiting the Disneyland Resort in California, USA, or Disneyland Paris. So I'll try to point you in the right direction for either situation.
For the Disneyland Resort in California, guests can
modify their theme park reservations online up to 24 hours in advance. If you booked a complete vacation package then I would recommend calling the
Vacation Packages phone number to ask a Cast Member for assistance, those options may be limited due to your soon arrival date.
If you're planning to visit Disneyland Paris then I would look at the
"What happens if I miss my registered dates" on the Disneyland Paris ticket registration page. According to the site, guests can currently cancel their registration up to 10:00 AM Paris local time on the day of their visit to register for a new date. Hotel packages have different policies and procedures for rescheduling, so if you have further questions you should
call and speak with a Cast Member directly. Whether you're heading to California or France, both Disney Resorts have wonderful first aid centers available for guests! If anyone in your party starts to feel poorly please don't hesitate to ask a Cast Member where you can get assistance. I want you to be able to enjoy your visit as much as possible!
I hope your daughter feels better very soon, Donna! Wishing you safe travels and a wonderful holiday.
Keep moving forward!
Amanda