How to export/import CSV file?
Go to Reviews tab and click on “Export/Import Reviews” button for desired product.
If you choose to export reviews, CSV file will be downloaded to your computer.

If you need to import reviews, click on “import reviews from CSV” and choose a file.
CSV file format must contain these columns in this order:
“id review”, “id product”, “nickname”, “first name”, “last name”, “comment”, “stars”, “date”, “country code”, “likes”, “buyer link”, “sex”, “active”, “source”, “order”, “email”, “photo count”, “photos”.
You can download sample here