A forum member cannot delete a thread or the first post – even as a the author of that post.
For any subsequent post in the thread, the forum member creating the post can alter the title of the post or delete the post.
If you do need a thread to be deleted AND your post is the first and only posts, then you can ask a Moderator to delete the thread for you.
From my own viewpoint, in general, where others have already responded to a first post the Moderators would not delete a thread without very good reason (spam, obscene, etc) as the history of the technical content of the thread should be retained.
