Hi Alice,
It's great to see you here with us at planDisney!
When you're making reservations to visit the Disneyland Resort theme parks through the
Theme Park Reservations system, it's helpful to know that you can make reservations, and you can cancel reservations, but there isn't a feature to modify reservations.
It's also helpful to know that the online theme park ticket purchasing system now lets Guests
conveniently purchase theme park tickets and make theme park reservations at the same time.
One option for you to explore is to have the Guest you're looking to add
check the theme park ticket buying site to see if they can purchase a ticket and make a reservation for the same date and starting theme park as your reservation. You could also look at canceling your reservation and making a new reservation. You would want to be sure to
check the Theme Park Reservation Availability calendar to see that the theme parks have reservations available for the dates you wish to visit.
Alice, here's wishing you lots of fun when you visit Disneyland Resort, and here's wishing you lots of Disney magic in your day today!
Jerry