It shall be the responsibility of the commission to hear all applications for zone changes and changes in the zoning ordinance, as prescribed by law and this ordinance, and to recommend action to the city council. The commission has authority to approve conditional uses under the provisions of section 6.15. The commission has no authority to approve variances from the requirements of this ordinance. Requests for variances shall be presented to the building official and if within the province of section 11.2, the request shall be sent forward to the board of adjustment for hearing.