Make the reservation online and tell them its the new Ford Flex. I've rented open uhaul trailers twice with my new Explorer this way. One other time at a different location I had a guy call me out on the Explorer and wouldn't let the trailer go. I ended up going home and grabbing my neighbors Toyota, renting the trailer and taking it home to hook it to the Explorer. I used it all day and took it back with the Explorer, the check-in guy said "hey, your not allowed to pull this trailer with an Explorer". I told him but I did it anyways and look, I brought your trailer back in one piece. He just looked at me and walked away.