The power herein-after given to discharge any lands from feu duties or casualties of superiority, as well as every other power required to be exercised by any superior pursuant to the provisions of this or the special Act, or any Act incorporated therewith, and the power to discharge lands from any rent, payment, charge, feu duties, ground annuals, or other real burdens or incumbrances, and to agree for the apportionment of any such rent, payment, charge, feu duties, ground annuals, or other real burdens and incumbrances, shall extend to and may lawfully be exercised by every party herein-before enabled to contract for, sell, dispose of, or convey lands or rights or interests therein to the company.