You are welcome!
You can do that here on the codecanyon item page: https://codecanyon.net/item/ajax-search-pro-for-wordpress-live-search-plugin/3357410
By clicking on the stars on the sidebar (by the Rate the item text) I think it should bring up a dialog, where you can enter a text as well.
Or on your codecanyon downloads page: https://codecanyon.net/downloads
Similarly, there should be a list there of your purchased products, and clicking on the stars should bring up the same dialog.
The WP plugin page only stands for the free version, which is a different plugin 🙂