Now I want to sell the same product on my own website www.a2zwebhelp.com. Is it possible to change the term and condition to sell the product on my own website?
Only if your product is published on Envato Market on a non-exclusive account.
Yours is exclusive, so either you opt-out from being an exclusive author on Envato Market, either you create a second account (non-exclusive) where you publish items that you also want to sell on your website.
With one remark that you can’t delete the item from your current account and publish it on the second account, this is not allowed.