Transfer of Engagements. If a horse is sold by private treaty, at public auction, or claimed out of a claiming race (unless the conditions of the claiming race stated otherwise), the horse is considered to be transferred with its engagements. The written acknowledgment of both the buyer and seller is required to negate the provisions of §A(1) of this regulation. Registrations and Transfers of Horses. After a horse has been registered with the Racing Secretary, listing its owner, unless claimed at the meeting, the entry of the horse on behalf of a person other than the registered owner is not permitted until the stewards receive proof of a change in ownership. As proof of a change in ownership, the stewards shall require: A notarized bill of sale from the registered owner; or Other evidence that is satisfactory to the stewards that the registered owner has transferred ownership. The change of a trainer of a horse may not be approved by the stewards until a written or verbal authorization is received from the owner of the horse.