Hi Angie, welcome to planDisney!
Let's kick this off with some good news!
Theme park tickets are not officially assigned to a Guest until the Guest enters the
Disneyland Resort Main Entrance Turnstiles. At that point, the Cast Members there will scan the ticket and take a picture of each Guest to assign the ticket to them. Once the ticket is assigned to a Guest, the ticket is then nontransferable. But in your situation, as one of your party members is unable to make the trip, either that Guest is free to use the ticket another time, OR another person can attend in their spot. Good news, right?
As you begin to play your magical vacation, I wanted to check to see if you've added the new
Disney Genie+ service add-on to your tickets? If not, you can purchase Genie+ once you've entered one of the theme parks through the
Disneyland Mobile App. I recently returned from a trip to the Disneyland Resort and heavily used Genie+. Genie+ was a lifesaver, as it allowed me to access the
Lightning Lane entrances for certain attractions, instead of waiting in the standby line. Game changer! AND, as a bonus, you also get unlimited
Disney PhotoPass Digital Downloads with your purchase of Genie+!
I hope you have the most magical time, and if you have any more questions, visit us again!
See ya real soon!
Jin