Although you're unable to delete a review, you can edit the star rating, photograph (on the Etsy app), and the written note any number of times while the review is still eligible to be left. This article explains further.
Note: If you leave a review of 3 stars or fewer, and the seller responds, you won't be able to edit the review, even if the seller deletes their response.
On Etsy.com
Go to You > Purchases and reviews. Find your order and click Edit Review.
On the Etsy app for iOS and Android
On the iOS app, tap You > Purchases and reviews.
On the Android app, tap the three line menu and then tap Purchases.
Find your order and tap Edit Review. If you’re editing a photograph for a five star review, you’ll have the option to edit the photograph as well. If you lower the rating from five stars, the photograph will automatically be removed and you will be required to leave a minimum five word review.