Writing for All was a platform where users could write novels and comment on other users 'novels. However, whether or not users are allowed to delete their own book reviews, this specific platform may have different rules, so I can't give a definite answer. Generally speaking, it was possible to delete comments on the platform, but one had to abide by the rules of the platform and relevant laws and regulations. Some platforms may require users to sign confidentiality agreements or similar documents to protect users 'privacy and comments from being leaked. Please note that deleting a comment does not necessarily mean that you have completely withdrawn your views on the content of the comment. If the user violates the rules of the platform or relevant laws and regulations, the platform may take other measures such as limiting the user's comment rights or other treatments.