Local Government Code of 1991
Section 10. Plebiscite Requirement. - No creation, division, merger, abolition, or substantial alteration of boundaries of local government units shall take effect unless approved by a majority of the votes cast in a plebiscite called for the purpose in the political unit or units directly affected. Said plebiscite shall be conducted by the Commission on Elections (COMELEC) within one hundred twenty (120) days from the date of effectivity of the law or ordinance effecting such action, unless said law or ordinance fixes another date.