When a municipality now existing, which has not adopted the code charter or commission form of government, but is governed by another charter, shall desire to amend its charter, the same may be done in this way: the mayor and board of aldermen, city council, or municipal authority, by whatever name known, may prepare, in writing, the desired amendment or amendments and have the same published for three (3) weeks in a legal newspaper published in the municipality, if there be one, and, if none, then by posting for said time in at least three (3) public places therein, after which the proposed amendment or amendments shall be submitted to the Governor, who shall submit the same to the Attorney General for his opinion. The publication of the amendment or amendments may be made as provided in Section 21-17-19. If the Attorney General is of the opinion that the proposed amendment or amendments are consistent with the Constitution and laws of the United States and the Constitution of this state, the Governor shall approve the proposed amendment or amendments. If, after publication is made, one-tenth (1/10) of the qualified electors of the municipality shall protest against the proposed amendments, or any of them, the Governor shall not approve the ones protested against until they shall be submitted to and ratified by a majority of the electors of the municipality voting in a special election. Amendments, when approved by the Governor, shall be recorded, at the expense of the municipality, in the office of the Secretary of State and upon the records of the mayor and board of aldermen, or other governing authorities of the municipality, and when so recorded shall have the force and effect of law. No amendment to the private or special charter of any municipality shall be adopted or approved when such amendment is in conflict with any of the provisions of this title expressly made applicable to municipalities operating under a private or special charter, or is in conflict with the provisions of any other legislation expressly made applicable to any such municipality.