Hiya, Melissa!
Welcome Home and welcome to planDisney! How exciting that you are planning for your upcoming visit to Walt Disney World Resort and it looks like your vacation is just around the riverbend. Getting to see each of the four theme parks in one vacation sure is a wonderful way to maximize the magic, especially with the current 4 Day, 4 Park Magic Ticket.
Melissa, if you are a
Disney Vacation Club Member, you can contact
Member Services who can look into this for you. They may be able to upgrade your three-day ticket to the
4-Day, 4 Park Magic Ticket and just charge you any balance for the difference in the total price. Now, the 4-Day, 4 Park ticket can't be upgraded or modified, however, it doesn't specify if you can upgrade from a three-day ticket TO the 4-Day, 4 Park Magic Ticket. Typically, you can upgrade unused tickets so one that is equal or greater in price, but as this is a special offer, there may be restrictions. However, Member Services will be able to help you.
If you are not a DVC Member, you can contact
Guest Services who can look into the same option. Since the tickets are unused, they may have some flexibility here to do this for an upgrade to the 4 Day, 4 Park Magic Ticket, or be able to offer you another solution, but you would need to call them to inquire.
I hope this helps you, Melissa! If you have any further Disney vacation planning questions, stop back and see me here. I'll be so happy to help you! Have the most magical vacation on earth!
See ya real soon,
Keri