Assuming you have the vision package, then what they can activate is the towing assist. This is a feature that, after you put a sticker with 3 black dots on your trailer, helps you align the trailer when backing up or attaching the hitch. If it is active you will know by checking your camera view as a new "Towing View" will now be present, even when no trailer is attached. Apparently LRNA has not done a very good job of explaining this feature to the dealerships and how to activate it, so find a dealer and service advisor that has done it before or you may be in for some run around.
Other features such as trailer stability, to my knowledge, do not need any activation. Trailer lights, braking, etc, are all fine without any dealer activation.