Hi @motherbear, if you go to the little blue box in the top right hand corner of your published post and click on it, the first option allows you to edit your post, which won't create a duplicate post.
I try to not make too many edits after I've published my post, as it sends a notification to whoever you've @ mentioned, each time you make an edit which can be confusing too. I get distracted having a 15 yo at home 24/7, and my login can time-out sometimes! I've found that if I log back in, go back to the post I had initially responded to (it has to be the same one), it'll come up saying you had a previous post saved, which you can load or discard. Finding that out was a saviour for me!
(15 yo currently cackling away in her bedroom. I just love that sound! 
)
