Yes it can be done. The degree of difficulty, though, depends on a couple of things.
SCENARIO #1
The room you currently have has enough occupancy space that adding your parents will not exceed the limit. For example, if it's just you and your daughter now, then adding your parents won't exceed the room limit (four or five, depending on resort and room type). In this case, you can just call and add them to the reservation. You'll be charged a nightly fee for having 3 adults in the room, but way cheaper than a third room. Leave your daughter on your reservation until you arrive at the resort. At that point, just go to the front desk and tell them she's going to be staying in her aunt's room. They'll make the adjustment and reset her magic band to open that door instead. You can also get a key cards for your room that you can give her or your sister to gain access to your room as well.
SCENARIO #2
Adding your parents would exceed the room limit, and you need your daughter to move to the other room in order to accommodate everyone in the two rooms. This situation is a bit more complicated, as you need everyone on a reservation. Moving your daughter to your sister's room will require the purchase of another ticket for her, as packages require everyone on the reservation to have the same ticket type.
There are a couple of ways to handle this.
1) daughter gets the package ticket, and you transfer the ticket you already purchased to one of your parents (yes, completely unused tickets can be transferred to someone else). You could also just keep that ticket for a future trip.
2) your sister can change her reservation to a "ticketless" package. This will remove the ticket she currently has from the package. She will then need to purchase a new ticket. Your daughter can use the existing ticket she has.
Hope this helps.
Steve
