Wis. Stat. § 114.74: Refunding bonds.

(1) The authority may issue bonds to fund or refund any outstanding bond, including the payment of any redemption premium on the outstanding bond and any interest accrued or to accrue to the earliest or any subsequent date of redemption, purchase, or maturity.

(2) The authority may apply the proceeds of any bond issued to fund or refund any outstanding bond to purchase, retire at maturity, or redeem any outstanding bond. The authority may, pending application, place the proceeds in escrow to be applied to the purchase, retirement at maturity, or redemption of any outstanding bond at any time.