I do not advise removing directly from the database as data may have dependencies one might end up with orphan records.
With the post ID (add it in ADDPOSTID), save the script bellow and add the PHP file in the root of your WordPress website, login as Admin and call the file directly on your browser:
if ( current_user_can(...
This is not possible using the standard comment form. Comments in WordPress are built around post IDs, and are coded with this assumption down to the foundations. Even post statuses that can receive comments are hardcoded at multiple levels.
The comment form itself knows where to go afterwards via the comment_post_ID input.
You will not be able to repurpose ...