Yes, it is relatively simple. In the published content open the html page that the button is on using any text editor, notepad works fine, search for the URL and make changes as necessary. Resave.
In the attached, I set the button to open google. Open page_1.html (in HTML folder) in notepad. Search for “google”. When you find the URL change google to something else like trivantis. Resave and open by double clicking the index.html. click the button and you should now go to the revised site.