Hey there Cameron,
Welcome to planDisney and thanks so much for your question!
I'm happy to share that the names on your tickets are more for your organizational purposes - for wholly unused standard
theme park tickets, the name does not determine who is able to use them but rather there to help you keep them sorted out between party members.
Once someone scans their ticket for the first time to enter a park, there will be a photo taken of the ticketholder which will then lock in that ticket to that Guest for the remainder of its duration. Therefore, if a ticket has already been used, it must then be used by the same person for the rest of it's available use. There are also certain promotional tickets I've seen in the past that require additional identification details to determine the ticketholder is eligible to use that special offer ticket.
If you'd like to get the name of the ticketholder changed so it appears with a new name in your Disneyland Resort mobile app, you'll want to
call a Cast Member at the Tickets line. They are typically able to see more details about your ticket and can usually get those names changed as needed if it's a standard ticket.
Thanks again for stopping by with your question, Cameron! I hope you enjoy your upcoming visit to the Happiest Place on Earth.
Have a Magical Day,
Greg