Hi there, Pamela! Welcome to the Disney Parks Moms Panel.
Pamela, I think that you are referring to the list of
Cards and MagicBands that are linked to your
My Disney Experience account. Deactivating these cards simply freezes them. This is especially useful if you happen to have misplaced one, which I have done on more than one occasion. If you have charging privileges linked to your card or MagicBand be sure to deactivate your cards as soon as you realize they are missing, so you don't find a few surprise charges from Oaken's big summer blow out! If you happen to find your card or MagicBand, there is no need to ask Elsa to bring back summer. You can simply click the activate button to the right of the card or MagicBand on your My Disney Experience Account.
Once a card or MagicBand has been assigned to you, it is yours forever. So you will not be able to assign it to another family member.
I hope that this helped, Pamela. Please come back to the Disney Parks Moms Panel if we can answer any other questions for you!
Sarah B.