Hello there, Nerissa!
A warm welcome to you and thank you for bringing your question to us here at planDisney! I see that your visit to the Happiest Place on Earth has already occurred, but I will try and answer your question to the best of my ability for future reference.
We here at planDisney are knowledgeable and enthusiastic Disney guests, but we are not affiliated with Costco in any way. We still try our best to help other guests who come here to have their questions answered. Therefore, I called a Costco Travel Agent on your behalf because I was genuinely curious about the process. She was very helpful and informed me that, once purchased, your vacation package should be visible within the
Disneyland mobile app and on the
Disneyland website. She stated that changes could be made there if availability existed, such as adding a day at a
Disneyland Resort Hotel. Otherwise, she recommended giving Costco Travel a call (there was a specific line for Disneyland packages) and speaking with them. She seemed to indicate that making changes to your travel package, like adding a ticket, was not an issue.
Fun Fact: The term "E-Ticket Ride" comes from the old
Disneyland ticket books, which were in use up until 1982 when they were phased out and replaced by passports.
I hope you were able to enjoy your trip to the Disneyland Resort, Nerissa. Many people consider the post-Holiday season to be the best in terms of crowds and you still get to enjoy the seasonal
Holiday events and decorations that were on display!
Sincerely,
-Al