Assume the following facts: The Walkers bought a home in a subdivision developed by Sloan. Due to an error by the closing attorney, the deed conveying the home to the Walkers included not only their lot but also the adjoining vacant lot. When Sloan discovered the error some months later, he approached the Walkers regarding the execution of a corrective deed. The Walkers refused even though they knew they had not contracted for the vacant lot. In paragraph format, what possible remedies does Sloan have?