I just did this yesterday. The reservation will show the Honors number of the account where the points came from and the diamond desk told me they cannot change it to a different number but the hotel can. After making the reservation I'd suggest contacting the hotel directly and informing them the staying member is also a diamond and give them their number.

I would not have your name on the reservation as the hotel could refuse your award stay if you did not check-in as well as being in violation of the T&C.