At the bottom of every post you make, you will see a "Reply" button and an "Edit" button. When you edit the first post in your thread, you can also edit the "Subject", which will change the title of your thread.
1. Go to the very first post in your thread. Click "Edit".
2. Edit the "Subject" of that post.
3. Click "Submit" to save your new title.
Now you can easily let people know when you have something new to share!