Local Government Code of 1991
Section 441. Manner of Creation. - A municipality may be created, divided, merged, abolished, or its boundary substantially altered only by an Act of Congress and subject to the approval by a majority of the votes cast in a plebiscite to be conducted by the COMELEC in the local government unit or units directly affected. Except as may otherwise be provided in the said Act, the plebiscite shall be held within one hundred twenty (120) days from the date of its effectivity.