This endpoint allows you to add an existing device to an existing vehicle. You can use this route with a device with no previous vehicle or a device already assigned to a different vehicle. If the device is already assigned to a different vehicle, the association will be updated. The old vehicle will no longer have a relationship with this device, and the new vehicle will from that point forward. If the vehicle already has a relationship with a different device, that association will be updated also. The old device will no longer have a relationship with this vehicle. This route will return the updated details of the device passed in.