Any city that has operated for more than six years under or since changing from the city commission system of government may change its governmental organization and adopt the city council form of government or the modern council form of government or revert to the city commission form of government. The proceeding to change or revert shall be initiated either by a resolution by the governing body or by a petition asking for such change signed by not less than twenty-five percent of the qualified electors of the city. In no event, however, shall the petition contain less than thirty signatures. In any city having six or more municipal election precincts, not more than twenty percent of the petitioners may reside in any single precinct. For purposes of this section, the term “qualified electors of the city” means the total number of qualified electors voting for the office of the chief executive officer of the city at the preceding city election. The signatures to such petition need not be appended to a single paper, but one of the signers upon each paper shall make oath before an officer competent to administer oaths that each signature appearing upon such paper is the genuine signature of the person whose name it purports to be and that such person purports to be not less than eighteen years of age and a resident of the city. Each petition, in addition to the names of the signers, shall contain the name of the street upon and the number of the house in which each petitioner resides. Any petitioner shall be permitted to withdraw that petitioner’s name from a petition within five days after the petition is filed. If the proceeding to change from or revert to a commission system of government is initiated by petition, the question may not be placed on the ballot more often than every four years.