How can I delete other PC's that I took off after renewal with Norton 360?

I am not using Norton 360 on my Sister and Brother in law's computers . I want to have my 2 other available for my other PC's I have bought. I just renewed for another year ..How can i delete the other 3 or 2 PC's from mynortonaccount.com or I do I have to call Symantec up?

I am not using Norton 360 on my Sister and Brother in law's computers . I want to have my 2 other available for my other PC's I have bought. I just renewed for another year ..How can i delete the other 3 or 2 PC's from mynortonaccount.com or I do I have to call Symantec up?