看一下你的PS agreement 上有没有appraisal value can't be lower than your purchasing price 的contigency 条款。有的话你可以要求退出。一般情况下是buyer and seller split the difference. For new house buyers, it's very important to make sure that you have the contigency of "appraisal value can't be lower than your purchasing price" on your PS agreement. it will protect you. If you had use buyer agent, he/she should have done this for you.