In theory, yes, but the seller has to follow the contract's process, and the rules are state-specific. Signing an appraisal-gap addendum does not by itself force the seller to accept whatever adjusted price results when the appraisal comes in low. If the seller wants more than your revised number and you decline, you are back in a negotiation rather than an automatically settled deal. What the seller can do next depends on your contract and your state. In California, for example, a seller generally cannot cancel on the spot; they typically have to issue a notice to perform first, and only if no agreement is reached after that can they lawfully back out. Other states handle cancellation differently, so the specific path is not universal. From the seller's side, walking away is a real gamble. Rejecting a buyer who is already offering more than appraised value, on the hope that the next buyer or the next appraisal comes in higher, carries genuine risk, especially when demand is softer. Often the rational outcome is meeting somewhere in the middle. Cancellation rights and remedies are legal questions that vary by state and by contract, so have your agent walk you through your specific paperwork and get a real estate attorney's read before anyone declares the deal dead.