Application. Application for a certificate of appropriateness to construct, alter, repair, move or demolish any structure within the Historic Preservation District or any historic site shall be made on a form, approved by the Planning Board, to be submitted to the Zoning Officer. In the event that the proposed modifications meet criteria that have been preapproved by the Planning Board, the Zoning Officer may approve such modifications upon application. Upon recommendation of the Historic Preservation Commission, the Planning Board shall issue a certificate of appropriateness at its next regularly scheduled meeting. Applications for modifications not meeting preapproved criteria shall be forwarded by the Zoning Officer to the Historic Preservation Commission. The Historic Preservation Commission shall classify it as a major or minor application. Then, in accordance with the provisions of Subsections e and f, it shall provide written recommendations regarding issuance of a certificate of appropriateness to the Planning Board within 15 days of the receipt of the application by the Historic Preservation Commission.