Iowa Code § 298.20: Funding or refunding bonds.

For the purpose of providing for the payment of any indebtedness of any school corporation represented by judgments or bonds, the board of directors of such school corporation, at any time or times, may provide by resolution for the issuance of bonds of such school corporation, to be known as funding or refunding bonds. The proceeds derived from the public or private sale of such funding or refunding bonds shall be applied in payment of such indebtedness; or the funding bonds or refunding bonds may be issued in exchange for the evidences of such indebtedness, par for par.