(1) The board of trustees has the power to and is authorized to refinance, in whole or in part, from time to time, its valid outstanding obligations issued under this subchapter and any amendments hereto.
(2) To that end, the board of trustees may issue refunding bonds.
(3) This power may be exercised successively, and any obligations which have once been refunded may thereafter from time to time be refunded.
(4) Refunding bonds shall be issued in the same manner as provided in this subchapter for original obligations.