Once an episode has been deleted it cannot be recovered as the original file. If the episode was broadcast within the last 60 days it is possible to regenerate it as a new episode using the Create episode functionality, however if not then the episode will be lost forever. Please be careful.
To delete an episode navigate to the episode page and then select the delete episode button at the top of the page. You will be prompted to confirm this choice and can either accept or cancel the changes.