You are able to edit your posts after you have created them. This comes with a small caveat though, all of the reviews that are left on your post will disappear and your post will no longer be approved for display (assuming it already was).
Find the post you’d like to edit and click the ‘Edit post.’ link underneath it, you are only able to edit your own posts. On the edit post page, you are able to rewrite text and change the image attached to your post.
You can delete your own posts by clicking the ‘Delete post.’ link underneath a post. Click the ‘Ok’ button on the pop-up window to confirm your action.