Two ways.
No. 1
If you want to visit in person, then visit Lahore excise office and ask for alteration/updation form, fill it, pay fee, and submit form. It may cost your full day because of rush. And don't forgot to bring all original documents.
No. 2
You can hire an agent. He will charge little fee and will do it. Most probably you don't need to give him whole file, but just smart card and he will take care.
I know one very trusted agent there through whom I transfer my vehicles over a decade.
