How do I update a lien, I need to add interest to the lien

It would depend upon the statute in your particular jurisdiction which provided for such a lien. I assume you filed or recorded some sort of a notice of lien originally. You would record the corrective lien in the same place.

What sort of a lien is it, and what state or other such jurisdiction are you in?

From your other post, it appears that you are talking about a North Carolina HOA lien. You would correct the lien by complying with the terms of § 47F‑3‑116 (http://www.ncga.state.nc.us/enactedlegislation/statutes/html/bychapter/chapter_47f.html).

I live in Onslow countyN.C. the lien was placed on a property for not paying HOA dues for the past 2 years, I want to update the lien and at the present time I am working on bringing them to court to collect the almost $800.00 in back dues.