Communicate with the developer, personally think it should be exchangeable, unless he has no house for you to exchange, otherwise he will not sign the contract. It was brave of you to pay the down payment without signing anything. But it may be difficult for you to enjoy more discounts when you change rooms, because you lack bargaining chips.

50 to 60, I really don't think there is much change, or I'll get more than 80 on the cable station to save trouble in the future.

When buying a house, I thought too much money, but I didn't buy a jump floor. I regretted it for two or three years, you know. First, it is very troublesome to change the house after buying it. Instead of taking a step back, it is better to meet your long-term needs as much as possible; Second, after two or three years, I can afford a higher mortgage, but it is too much trouble to change rooms, especially under the current policy. Of course, don't blindly seek big, at least have a baby and pick up the old man is enough.