I just traded in a 2015 S4 plus some bucks for an upscale 2015 S4. The dealer had only one key for the car I bought. Anticipating such a situation, but not knowing whether it would be useful, I kept the second key for the trade-in in my pocket. My question is can the second key I kept be reprogrammed to perform all the needed functions, i.e. ignition, remote ignition, as well as other remote functions, for the new-to-me car?