hi: yes you can purchase a ump or uph (don't really know the correct term-i still call it the length of stay pass) for a guest. we do this all the time because we are ap holders as well.
We'll have the same situation in January. My inlaws will be checking in 5 days after us and the reservation is in their name. Can they get the 10% off themselves or do we need to be there when they check in and purchase them ourselves?