Section 13August 1, 1989, Sec./Art. 13

The creation of the Autonomous Region in Muslim Mindanao shall take effect when approved by a majority of the votes cast by the constituent units provided in paragraph (2) of Sec. 1 of Article II of this Act in a plebiscite which shall be held not earlier than ninety (90) days or later than one hundred twenty (120) days after the approval of this Act: Provided, That only the provinces and cities voting favorably in such plebiscite shall be included in the Autonomous Region in Muslim Mindanao. The provinces and cities which in the plebiscite do not vote for inclusion in the Autonomous Region shall remain in the existing administrative regions: Provided, however, That the President may, by administrative determination, merge the existing regions.