Upon preliminary approval by the State Bond Commission pursuant to the provisions of § 3-21, the state, acting by or through the Commissioner of Housing, may enter into a contract or contracts with an authority amending the provisions of any contract or contracts for financial assistance with regard to any housing project entered into before June 13, 1961, pursuant to the provisions of this part to conform the provisions of any such contract so entered into to the provisions of the contracts authorized by law in effect on and after said date.