How do I add a search input tags to disable 3rd party search plugins on anspress search

I have a search plugin installed on my site called Instant Search Plus and it has hijacked the Anspress search.  Ive done some research and found out that I need to add an isp_ignore attribute to the search box input tag to make the search ignore my plugin.

So how do I ad an isp_ignore attribute to the search box input tag that Anspress uses?