In submitting this State’s certificate of ascertainment as required by 3 U.S.C. § 5, the Governor shall certify the State’s presidential electors and state in the certificate that: the presidential electors will serve as presidential electors unless a vacancy occurs in the office of presidential elector before the end of the meeting at which presidential elector votes are cast, in which case a substitute presidential elector will fill the vacancy; and if a substitute presidential elector is appointed to fill a vacancy, the Governor will submit an amended certificate of ascertainment stating the names on the final list of the presidential electors.