Hi Alberto! Thanks for bringing your question to planDisney.
I checked on a couple of things for you. First, theme park reservations are still
currently available for your new preferred day. This can change quickly, however, as parks and days can fill up. The availability of theme park reservations isn't guaranteed. So, you'll want to make your new reservation as soon as possible. I also checked on the tiers for your old park date and your new one. One-day tickets are priced by tier, and your
new date is a higher tier, which means you'll need to pay the difference.
Plans sometimes change, and luckily, many valid standard one-day tickets are
eligible for upgrades if you need to visit on a higher-tier day, according to the current terms of purchase. To speak with a Cast Member about purchasing a new higher-tier ticket and applying your current ticket to the new purchase, please call the
Tickets phone line. They're always happy to assist! You might also be able to change your tier directly in the
Disneyland mobile app. From the three-bar menu, select the "My Tickets & Passes" tile. Look for the "Change Ticket" option on your ticket to change to a higher tier by paying the difference.
May is one of my favorite times to visit. If you're Star Wars fans, be sure to visit Star Wars: Galaxy's Edge. We ran into our favorite droid, R2-D2, and Luke Skywalker, roaming this weekend. The Disneyland mobile app can help you find your favorite Characters. Change the selection on the map to "Characters" and look for the Mickey icons. Tapping an icon will bring up which Characters you can hope to meet in these areas, along with their schedule, which is subject to change or cancellation.
I hope this helps!
Elizabeth