Want to extend service contract

How to extend a service contract?  Sorry, had to label this wifi routers because no labels apply for what I need.  I don't own any Netgear hardware products.  But I have had a tech support contract with Netgear to help me with my home computer, Xfinity wifi, etc.  I bought a 6 month contract that expires 6/30/19.  I want to  buy a one-year contract.  I can't find anywhere on this site to do this.  How do I do it? Thanks!