if you have the copy of registration book, delivery order with date, time & sale receipt with buyer's cnic make copy of the same write a cover letter that the car make & model year registration number so n so has been sold to mr. so n so cnic number so n so on zx.01.2099 (date). I'm not the current owner of vehicle please update your records. & send by TCS to the motor vehicle registration office. civic centre Karachi
attach copy of all relevant papers of sale
.. keep TCS receipt as evidence.
if you do not have any such paper in your custody, so HELP YOU GAWD