Originally Posted by
Auracon
This is consistent with what I have been told a few times before. Even for GS traveling on a reservation ticketed by another GS member's miles had to be upgraded with a GPU only from the mile-originating account.
I was once able to apply a GPU to a GS'ers award ticket booked with his/her miles, and I was a 1K. I think it's a manual process and YMMV depending on agent.