Hey there Eileen,
Welcome to planDisney and thanks so much for your question! It looks like you're planning a trip to the Happiest Place on Earth to ring in the new year - how exciting!
If you're using the "Build Your Vacation" tool at the top of the
Disneyland Resort home page to plan your upcoming trip, then you do have a couple of options throughout the process to modify the number of days of your theme park tickets.
It will first walk you through booking your hotel room and type. Then, you will see an "Add Park Tickets" screen. The first step will offer 2- or 3-day ticket options (with 3-day tickets being the default selection). However, you'll also find a blue link just above the ticket options and also just below the blue "Continue" button on the right side bar that says "Continue Without Tickets."
For your situation, where you're planning on visiting the parks for one day, this is the link I would recommend you select on this step. It will then bring you to the payment screen and you'll be all set there. Next, you'll want to visit the
Theme Park Ticket purchase page to buy your 1-day tickets, which will also walk you through setting up your
theme park reservations as part of the purchase process.
Thanks again for your question, Eileen! I hope you have a wonderful time on your visit to the Happiest Place on Earth.
Have a Magical Day,
Greg