If you manually edit an episode, then Plex will use that information instead of the online information.
If desired, you can revert to the online information by performing the Plex Dance for each episode you want to change back. An alternate process is to re-edit the episode, unlock the manually edited fields, then refresh the metadata. Personally, I find the Plex Dance easier, but both should work.
If you are happy with the manual edits, there is no reason to revert.
