Hi, Blair!
What? Surely I read your question wrong! Who would not want to visit Walt Disney World??! Well, his loss is your twin sister's gain!
Without knowing your ticket type, package, etc., it is hard to give you a definite answer on
changing your reservation. Please call (407)934-7639 to speak to a friendly Cast Member. They can look at your reservation and let you know what your option are.
If you plan to fly, I would hold off purchasing any airline tickets, as these are often difficult to modify. If you made any
Disney Dining reservations, you do not need to change names for that, as your sister can just take his place.
Hopefully this will all be a simple change. Wishing all of you a magical vacation!
Cathy