Hi Kayla! Thanks for bringing your question to planDisney.
I checked on this for you, and I have magical news. Although your room choice might need to be adjusted, depending on how many the room can sleep, as long as there is availability, you can always add a Guest to a
Vacation Package. So, you can rest easy when booking a package and making a deposit, knowing you'll have the option to potentially add another person later.
The easiest way to add a Guest to your existing package is to call the
Vacation Packages phone line. A dedicated Cast Member can determine if you need a different room and inform you about availability. They will also arrange
admission tickets for the Guest. The addition of another Guest, including tickets and possibly an upgraded room, will adjust the final cost of the package of course. You'll be responsible for the difference. I'd have my method of payment handy when making the call.
I hope that helps! Have a magical day.
Elizabeth