Re-export restriction: returning duties-paid postal consignments requires a Drawback claim following prescribed procedures, and partial reexports without duty are irregular. Re-export of a partial consignment is prohibited where the addressee has taken delivery on payment of duty; the only permitted method to return such goods is by claiming Drawback in accordance with prescribed procedures. Opening a parcel, removing part of its contents after paying duty, and repacking the balance for reexport without duty is unauthorized and irregular.