Amendments to this Charter may be submitted to the electors of the city by a two-thirds vote of the city commission, and shall be submitted to such electorate when a petition is filed by ten percent (10%) of the registered voters in the municipality at the last regular municipal election of the city, setting forth any such approved amendments as received by the city commission. The ordinance providing for the submission of any such amendment shall require that it be submitted to the electors of the city at the next regular municipal election if one shall occur not less than sixty (60) nor more than one hundred twenty (120) days after its passage; otherwise, it shall provide for the submission of the amendment at a special election to be called and held within the time aforesaid. Not less than thirty (30) days prior to such election the clerk of the City Commission shall mail a copy of the proposed amendment to each elector whose name appears upon the poll or registration books at the last regular municipal or general election. If such proposed amendment is approved by a majority of the electors voting thereon, it shall become a part of the Charter at the time fixed therein.