The proceeds derived from the sale of any refunding schoolhouse bonds issued under the authority of this subpart shall be applied exclusively to the purposes provided in Code Sections 20-2-450 through 20-2-472. None of such refunding bonds shall be exchanged except for outstanding bonds for which they were issued to retire. In no event shall the refunding schoolhouse bonds so issued exceed in amount the previously existing total schoolhouse bond debt of the district issuing such bonds with interest thereon.
OCGA § 20-2-473