回复：问题是我的老房子卖不掉，再加上新的，房子贷款是通不过的

When the time comes and you still can not sell your old house and the seller does not have any other offer, then you can talk with seller again to ask them to reduce the price and you also reduce the price for yours. Because most of the time the people don't like to see the house under the contract, they may not be able to get any back up offer, so you may hold them for a month and get a better deal.