Can you return a new car?

No. It is nothing more than a myth that the "Buyer's Remorse" or "Cooling Off Period", laws apply to the purchase of an vehicle of any kind, new or used. Those type laws do not apply to vehicle purchases in any state. Once you purchase a vehicle you own it. Also once you purchase a new vehicle it becomes a used vehicle the instant you drive it off the lot and is worth far less than before. Those type laws apply to unsolicited sales as in a door to door salesman or phone sales. The only way you could return a vehicle is if the selling dealer had such an offer as GM has done in the past, or if the selling dealer agreed to allow you to return the vehicle. Otherwise you are stuck with your decision to buy the vehicle.