Hello, Frank! Thanks for stopping by planDisney!
You'll be glad to know that you can absolutely upgrade your ticket to a
Magic Key! The best process for doing so would be to make a theme park reservation with your current ticket and visit the parks as you normally would. After you have entered the park that day, but before the Disneyland Resort closes that evening, upgrade your ticket to a Magic Key in the
Disneyland app. As a California resident, you will have the option of the monthly payment plan, or you can pay the difference in cost between your ticket and the Magic Key in-full.
Keep in mind that the activation/anniversary date for your Magic Key will be the day you upgrade your ticket. Additionally, from that point on you will make theme park reservations using an
availability calendar specifically for Magic Key holders. You can make reservations up to 90 days in advance and, with an Imagine Key, you can hold up to two reservations at a time.
I hope this information was helpful. Have a magical day!
-Linda