A store admin can edit any product review on the Reviews page in the store's Admin area (Catalog -> Reviews).
To edit a review, click on the Pencil icon on the review line.
The Edit review pop-up will open:
If a review is in Pending status, the pop-up will name "Approve review" and have options to approve or remove the review. Keep in mind that you can not remove a published review this way.
A store admin can change literally every line in the review details, including the rating itself. It is also possible to reply to a customer using the "Add response" link at the bottom.
Use the Update button for reviews in the Published state and the Approve button for pending reviews to save the changes.
Related pages: