Notwithstanding any general or special law, rule or regulation to the contrary, the uses of the land existing in Boston, Massachusetts owned by the Commercial Wharf East Condominium, and its condominium unit owners, is authorized to continue to function in accordance with the public purpose set forth in the Downtown Waterfront-Faneuil Hall Urban Renewal Plan, dated April 15, 1964 as adopted by the Boston Redevelopment Authority and the City of Boston, and authorized through Chapter 663 of the Acts of 1964 and Chapter 310 of the Acts of 1972, to rehabilitate the granite building on Commercial Wharf into a mixed-use condominium facility that permits the first and second floors of the condominium building to be used interchangeably as facilities of private tenancy for residential or office/commercial use and the remainder of the building to be used as residences, together with all ancillary uses including private parking as established under the Urban Renewal Plan, and later authorized through the Rehabilitation Agreement, dated May 10, 1974 and recorded at the Registry in Book 8710, Page 631, and, to the extent necessary, such use is hereby confirmed and ratified, and the public purpose is hereby recognized, as proper under Chapter 91 of the Massachusetts General Laws.