Alright, you'll now notice that on the post window beside Post and Preview, there's a new button: Save as Draft.
Obviously, this allows you to save a post as a draft rather than posting it right away. To access your saved drafts, go into your
Profile (via the button in the main menu up top). In your profile menu on the left, you should see:
Summary
Show Stats
Show Posts
Show Drafts On your drafts page, you will see your drafts and be able to either modify (edit) them or remove (delete) them. When you're finished modifying your draft, all you need to do is click Post and it'll post to the original thread.
Thank Ciarente for this suggestion