Hi Sophia, welcome to planDisney!
I have great news! As long as your
tickets are wholly unused you have options! If you are tickets are still active and have not expired, then you can certainly upgrade them to new tickets of higher value.
In the case that your tickets happen to be expired, per
Disney's eTicket Terms & Conditions, any wholly unused, expired Disneyland Resort theme park tickets (except for special event tickets or tickets purchased from a third party), can be applied towards the purchase of a new theme park ticket in equal or greater value to what was paid for the original ticket! So either way, you have options available to you.
The easiest way to move forward is by visiting the
Disneyland Resort Main Entrance Ticket Booths. But as you're located in Colorado, I realize that might be just a bit difficult! But no worries, you can also call the
Disneyland Resort Ticket Line at 714-781-4636 and the fantastic Cast Members can help!
I hope this helped, and if you have any further questions, please do visit us again!
See ya real soon!
Jin