Site.pro files don’t appear on their own on your account. If your current website is a Site.pro website, that means you must have opened the website builder and clicked Publish from there.
You can delete the Site.pro files yourself, however Site.pro will have overwritten various WordPress files to be able to setup your Site.pro website.
So you will need to restore the overwritten WordPress files. You will probably only need the index.php and .htaccess files for this. But the general process looks roughly like this:
Alternatively, you can just reinstall WordPress.