In all cases where any borough in this commonwealth has, by virtue of any general or special act of assembly, issued bonds, either with or without coupons attached, to secure any indebtedness of any such borough, it shall be lawful for the burgess and town council of any such borough to redeem any or all of the bonds so issued as aforesaid, before the maturity thereof, with the consent of the holders thereof, and issue new bonds to secure such indebtedness, at any lower rate of interest; the bonds so issued not to exceed in amount the amount of the bonds so redeemed.
53 P.S. § 49201