Just call and make the reservation over the phone with a Hilton reservations agent. That's really the proper way to accomplish this task. The room will be in the other person's name and she or he will handle any incidental charges.

As a bonus, you won't be violating the Terms and Conditions of the Honors program. As tkelvin69 notes, you won't find yourself in hot water if the hotel is one that strictly adheres to the policies.