Ind. Code § 27-3-1-4
Not earlier than thirty-one (31) days after the date of the meeting of shareholders of the domestic company at which the plan of exchange was approved by such shareholders, a certificate setting forth the plan of exchange, the manner of the approval thereof by the directors of the acquiring corporation and the domestic company and the manner of its adoption and the vote by which adopted by the shareholders of the domestic company or setting forth that the plan of exchange has been abandoned shall be signed on behalf of each such corporation by its president or a vice-president and shall then be presented in triplicate to the department at its office for filing. The department shall file one (1) copy of such certificate in its offices and shall deliver copies bearing the date and time of filing endorsed thereon to the domestic company and the acquiring corporation. Upon the filing of such certificate, the plan of exchange and the issuance and exchange provided for therein shall become effective, unless a later date and time is specified in the plan of exchange, in which event the plan of exchange and the issuance and exchange provided for therein shall become effective upon such later date and time.
IC 27-3-1-4