Refunding and refunding bonds; payment from pledged revenues

Refunding and refunding bonds; payment from pledged revenues. Refunding bonds may be made payable from any pledged revenues which might be legally pledged for the payment of bonds being refunded at the time of the refunding or at the time of the issuance of the bonds being refunded, as the board may determine, notwithstanding the revenue sources or the pledge of the revenues for the payment of the outstanding bonds being refunded is hereby modified.