You can't transfer your reservation but you can register the car to someone else and then they can pickup the car. It'll require a bit of trust and cooperation between the reservation holder and the person registering the car since the car will remain on the reservation holder's account throughout the configuration/financing/purchase process and can't be transferred to a different account until after the car is picked up.
This is the process I'm currently going through where the reservation is held by my brother-in-law and the car will be registered to his sister (my wife). I'd be nervous about doing it with a stranger.