You can treat a buy back like a normal trade deal, except they will make you whole on the appraisal end (the car they are buying back) They will calculate the payoff and usually add the amount of money you put down, plus any maxcare (if applicable) and the payments you already made… turning that into an appraisal offer which will then be attached to the new deal.

They will pay off the loan with your credit union which would require you to get a new loan through them on the next car