Ohio Rev. Code § 4517.63
All actions of the franchisor or its officers, agents, or employees with respect to the creation, modification, interpretation, or termination of the franchise, or failure to renew or extend the franchise or the original investment or the increasing or supplementing of the investment by the franchisee in the franchise and its stipulations as to facilities, purchases of goods, vehicles, accessories, parts, or commodities by the franchisee from the franchisor, the sufficiency of the franchisee's performance as a franchisee, advertising and promotional activity by the franchisee, and the franchisee's right to sell, assign, or transfer, or otherwise dispose of his business, shall be in writing and signed by the authorized representative of the franchisor.
R.C. §4517.63