Here is what the rule says

Choice Privileges Reward Nights (all members)
20.

A member may redeem a reward night for an immediate family member (spouse, partner, children, parents, in-laws, brothers and sisters). Immediate family members (spouse, partner, children, parents, in-laws, brothers and sisters) can use the free night even if the member is not occupying the room.

When booking a reward night for someone other than yourself, be sure to ask the reservation agent to include the name of the guest in the notes field of the reservation. When booking a reward night through your online profile, be sure to include the name of the guest who will be staying in the room in the “Special Request” field.


http://www.choicehotels.com/en/choic...es-regulations