If I understand your question correctly, this can be the solution:
The owner of the thread can only Mark the question as Helpful or Correct and vice-versa.
In your case making the reply as unmark Helpful or Correct, will help you getting back your discussion in question format.
That's the correct work around.
Cathy - Hope this helps!
Thank you for answering my question, Yashita. Strangely there weren't any been marked "correct" or "helpful" in any of the replies... But I tried to reload the thread using Chrome instead of IE. Magically, the thread is marked "unanswered".
As a test you can also test the ongoing thread as you are the author of the same.