Gmac Smart Lease Does Anyone Know How To Trade In A Car That Is Being Bought Through "Smart Buy" (GMAC)?

Does anyone know how to trade in a car that is being bought through "Smart Buy" (GMAC)? - gmac smart lease

I try to get rid of my Pontiac that I is "smart shopping" (the lease for the purchase of only 55% of the car instead of all the payments are low). I know that if I trade in another GM does not pay the balloon payment at the end but I do not know if this is true only if you buy a new car or a lease or smart buy, or you can just used to get rid of. I have tried in other private label, because I do not want another GM, but they have the balloon payment on what I have to pay end up losing too much money. Who knows how to get rid of this car? And you know if you can trade in 2 cars and buy new 1? Thank you to everyone who can help.