Michigan Compiled Laws, Chapters 760 to 777 Code of Criminal Procedure § 767.7g

Sec. 7g. (1) If a grand jury has been convened under section 7c(a),  1 and the attorney general seeks to expand the jurisdiction of the grand jury to include 1 or more additional counties, the attorney general may petition the court of appeals under section 7b(1)  2 to convene a grand jury which includes the additional county or counties. If the petition is granted, the court of appeals shall convene a new grand jury pursuant to section 7e  3 and shall dismiss the existing grand jury.

(2) If a grand jury has been convened under section 7c(b) and the prosecuting attorneys of all of the counties over which the grand jury has jurisdiction seek to expand the jurisdiction of the grand jury to include 1 or more additional counties, the prosecuting attorneys of the counties over which the grand jury had jurisdiction and the prosecuting attorneys of the additional counties may, with the approval of the attorney general, petition the court of appeals under section 7b(2) to convene a grand jury with jurisdiction over all of those counties. If the petition is granted, the court of appeals shall convene a new grand jury pursuant to section 7e and shall dismiss the existing grand jury.