The Powers of Sale and Exchange herein-before given to the Council of His said Royal Highness shall extend to the enabling them to sell any Lease which shall have been purchased or taken in exchange under the Provisions herein-before contained, and shall not have been surrendered or merged, and to exchange the same, either for any Lands held in perpetuity, or for any other Lease hereby authorized to be purchased, and to convey any Part or Parts of the Lands and Possessions of the said Duchy in exchange for any such Lease; and that on every such Sale or Exchange the Purchase Money, or any Sum of Money agreed to be received on the Part of His said Royal Highness for Equality of Exchange, shall be paid in the same Manner as is herein-before directed with respect to Purchase Monies on Sales of any other Part of the Lands and Possessions of the said Duchy; and the said Council shall on the Sale of any Lease, Term of Years, or Chattel Interest which shall have been purchased or taken as aforesaid, on Payment of the Purchase Money, or in case of an Exchange of any such Lease, Term of Years, or Chattel Interest, on the Conveyance or Assignment of the Lands and Hereditaments to be received in exchange being executed, cause the Trustee in whom the said Lease, Term of Years, or Chattel Interest shall be then vested to assign the same to the Purchaser, or as he shall direct; and every such Assignment shall be good, valid, and effectual; and the Parties claiming under any such Assignment shall hold the said Lease, Term of Years, or Chattel Interest discharged from any Trust for His said Royal Highness, His Heirs and Successors; and the said Council shall, in and by such Assignment, or by a separate Instrument, at the Option of the Purchaser or Person paying the same, acknowledge the Payment of the Purchase Money, or the Money, if any, to be received by His said Royal Highness for Equality of Exchange.