Unfortunately I have been unable to export my reviews so that I can import them over to a 3rd-party. The Shopify Product Reviews app is completely broken with multiple Javascript errors and http 500 and 502 errors. So you can’t access the admin area to export reviews.
I spoke with support and here is what they told me: “So I went ahead and checked this further with our team. As the Product Review app is no longer supported and depricated by Shopify, we are unable to provide additional assistance to it. At this point, they strongly suggest using a third-party app such as Judge.me app. Any troubleshooting will not work as of this time. We humbly ask for your understanding and patience.”
Unbelievable.