I believe it is not possible to make negative points reservations for GOH reservations. At least that is what my concierge told me. I had them go through my future booking to see if there were points attached to each reservation, they all did with the exception of one stay which is a Destination resort. I asked them to apply the points, there was no change in my total points balance, but I did get a confirmation email from the hotel. They have some strange systems on their back end.