Sometimes you've published an episode, but realize you need to make a final tweak or edit. To get back to the editing experience, you'll have to unpublish the episode.
Unpublishing an Episode:
Visit the Podcast series that contains the episode you want to unpublish.
You can find it under the "Podcast" tab on the app sidebar on the left.
Click on the episode that you want to unpublish.
Click the elipisis "..." menu in the top right corner
Click the "Unpublish" button in the drop down.
Then you'll be taken to the editing screen to make your edits and publish again.