Deletion of car financing with bank credit.

Hello guys, I bought a new car by financing in December 17 with 2000€ down payment. The sum is currently at approx. 11.500€. Momentary rate is 215€ mtl. I chose the car too quickly at that time and would have liked to have another, cheaper used (evtl Astra H o.ä) about 4-5 tsd. Since I can’t easily get out of the financing or return the car, I thought the following: I borrowed the approx. 11,500€ from my house bank, redeem the loan and then sell my current car. (Probably iwas would get between 10 and 11 tsd out). I would then buy another car and pay back the rest (about half of it) to the bank and pay off the remaining approx. 500€ in normal installments. What do you think of this idea? Apart from that, of course, I make a little minus when I sell. Dear greetings and nice weekend I wish.