Apart from the fact that I have never hearted of anyone who has exchanged their DL for a Spanish one, even being able to make an appointment. One just goes to the office and does it. But time will tell.
(I had a friend who insisted that his GF had to go the the police station to register her change of address. It was only after they went there he believed I was correct when I said it was the town hall not the police. But as we know, some people believe only what they want to believe).