The only way you can do it is thru the member from whom you rented the points. Not even another
DVC member could help since Member Services will only discuss reservations made with our own points.
About 2-3 days before your scheduled arrival the reservation should be dumped to the resort computer system. If you try calling the resort directly, they may be able to confirm over the phone. That's about your only other alternative.
This is one of the drawbacks of renting so I hope you were comfortable with this person before taking the plunge. Hopefully he/she is just temporarily unavailable.