Within thirty days after a petition to change from the council system of government is filed, the city auditor shall examine the petition and ascertain from the voters’ register whether or not the petition is signed by the required number of qualified electors. The city auditor shall attach to the petition the city auditor’s certificate showing the result of the city auditor’s examination, and if the city auditor finds the petition to be insufficient the city auditor’s certificate shall show the reason for such determination. An insufficient petition may be amended within ten days after the city auditor’s certificate is made. Within thirty days after an amended petition is filed, the auditor shall make an examination thereof, and if the city auditor’s certificate shows such amended petition to be insufficient, the petition shall be returned to the person filing the same without prejudice to the filing of a new petition. If the city auditor shall find the petition or the amended petition to be sufficient, the city auditor shall place the same with the city auditor’s certificate before the governing body of the municipality.