To change the title of a thread or post content, you need to select "Edit" at the bottom of your post.
Editing is only allowed for a certain period of time after the post.
Normally, you just add on a new post to your original thread with your updated info like price change or new contact info, etc.
If there is a serious issue with a post you may use the "report post" feature or ask for a moderator's assistance.
