Hi, Dawna!
I'm not sure if I quite understand your question, but I'm going to try to answer as best I can.
First, let's assume that you're talking about adding an additional person to your
Disney Dining Plan. When you have a package reservation, everyone on that reservation has to have the same Park tickets with options as well as the Dining Plan, if you've selected one. The only way you can add the Disney Dining Plan to another person is to add them to your reservation which would mean that you'd need to purchase the same Park ticket as everyone else on the reservation.
On another note, if you've got restaurant reservations for a large party and you're just wanting to add someone to those plans, you'll want to give Disney Dining a call at 407.WDW.DINE [939.3463] to see if there is availability. If there is, the Cast Member will be able to make that change for you over the phone.
I'm hoping that one of these suggestions helps with your situation. Please feel free to write back in if we can assist with any other questions you have.
Wishing you and your family a Pixie Dusted vacation!
~Jackie