My father booked 2 rooms at the Westin Palace Madrid, one for himself and one for me, arriving a day later both under his name.

I need to change my room to my name, CC#, and SPG# so that I get the points, AA miles, and Platinum amenities. However, when I called the PC, the agent I spoke with said that because it is a prepaid reservation that this is not possible.

The same room is available for the same price on the same nights, so I thought the easiest would be to cancel and reverse the charge for my room, and then immediately book it again under my name. Still, the agent said this could not be done.

How can I get this reservation under my name and CC?