Originally Posted by iexaltu

Makes sense. It certainly isn't that intuitive. When you pull up the reservation, update your information right under trip details. I believe your email address and phone number may be needed in order to make changes. Once you update that and save for all future visits, scroll down in your reservation to where you see "Services". Click on the button at the bottom that says additional services. Then click on seats and the the rest should be pretty straight forward. Let me know if you have more questions.