Hi LeighAnne,
Thanks for stopping by planDisney! Happy to help in any way that I can!
I just checked with Mickey and his pals, and YES! You can upgrade your
One Park Per Day Standard Theme Park Ticket to a Park Hopper any time prior to your visit! Just head over to the
Disneyland Resort and visit any of the main entrance ticket booths, they can help you out. But be sure to monitor the
Theme Park Reservation Availability Calendar, as One Park Per Day Tickets and Park Hopper Tickets have different reservation availabilities.
When you start to plan your magical Disney vacation, you may have situations where you need to change your current theme park reservations to a later date. If the need arises, have no fear, because it's super easy to do! First, you'll need to cancel your current theme park reservations by logging in to your Disneyland Resort account, selecting the "My Disneyland" link, clicking the "Ticket and Reservation Details" link and selecting the "Cancel Reservation" option. In the next step, you can cancel your reservations. After canceling your current theme park reservations, you can book a new reservation for your desired date and theme park! Easy right?
If you have any more questions, come back to visit us again! We're here to help!
See ya real soon!
Jin