Hi Guadalupe, welcome to planDisney!
I have great news, you can upgrade your
One Park Per Day Theme Park Ticket to a Park Hopper! Just stop by the
Disneyland Resort Main Entrance Ticket Booths, and the fantastic Cast Members there can help you out! But just so you know, the One Park Per Day Tickets and Park Hopper Tickets have different
Theme Park Reservation Availability. So when you chat with the Cast Member, please be sure to let them know your current reservation date, and they can see if there is availability for the Park Hopper tickets.
I also wanted to check with you to see if you've considered purchasing the
Disney Genie+ service? This is a new service that allows Guests to use the
Lightning Lane entrances for certain attractions at
Disneyland Park and
Disney California Adventure Park. The Lightning Lane entrances are supposed to be quicker than the typical standby lines. If you haven't purchased this service yet, you'll have to wait until you enter the theme parks on the day of your visit to purchase Genie+ through the
Disneyland Mobile app.
I'm excited about your trip, and hope you have the most magical time!
See ya real soon!
Jin