Okla. Stat. tit. 21, § 1623

Every person who, with intent to defraud, endorses any negotiable instrument in his own name, and utters or passes such instrument, under the fraudulent pretense that it is endorsed by another person who bears the same name, is guilty of forgery, a Class B3 felony offense, in the same degree as if he had forged the endorsement of a person bearing a different name from his own.