(1) The county legislative body may, from time to time, amend the number, shape, boundary, area or any regulation of or within any district or districts or any other provision of any zoning ordinance; but any such amendment shall not be made or become effective unless the same be first submitted for approval, disapproval or suggestions to the regional planning commission of the region in which the territory covered by the ordinance is located, and, if such regional planning commission disapproves within thirty (30) days after such submission, such amendment shall require the favorable vote of a majority of the entire membership of the county legislative body.
(2) Prior to adopting an amendment as authorized under subsection (a), the county legislative body shall hold a public hearing on the amendment, with at least fifteen (15) days' notice of the time and place to be given by at least one (1) publication in a newspaper of general circulation in the county. A complete summary of the amendment shall be published at least once in the official newspaper of the county or in a newspaper of general circulation in the county. The summary shall include a statement that a complete copy of the amendment is available and where the copy may be obtained. If the zoning ordinance rezones property, a description of the property that is rezoned shall be included in the summary.
(3) Notwithstanding this part or any other law to the contrary, any county having a charter form of government, adopted pursuant to title 5, chapter 1, part 2, may amend its zoning ordinance by means of resolution; and all zoning amendments passed by resolution prior to July 1, 1996, shall be deemed to be valid and shall not be attacked on the grounds that the amendments were accomplished by means of resolution rather than by ordinance.