Say you buy a product and its a bit below par so you fairly give it a 2 star rating. Have a friendly discussion with the merchant over what the consumer thought was lacking. The merchant a few weeks later updates the product with some/all of those fixes and the product is now a 3 or a 4 star product. But we can't change our feedback to reflect this and in such a case the merchant now has a unfair rating.

As a consumer I would like the ability to be able to add an ammendment or update a rating if its warranted.