Low Appraisal

What happens if the bank's appraisal come in lower than the agreed upon sale price? One of three things can happen. The seller can accept the banks price. Or, the buyer can say no to the entire transaction ( because the offer is contingent on getting a mortgage) . Or third, there can be a negotiation where buyer and seller each contribute to "meet in the middle".
If the house appraises, we are a matter of days away from closing. Really, after the loan is "underwritten", its just a matter of getting all parties to the closing table at the same time.