How to reset PLEX server

Quick question I think.

A family member is setting up a PLEX server on a PC they received from someone else. Where are the files to delete that resets PLEX back to defaults, i.e., a new server setup? He’s uninstalled and reinstalled, but it still shows as the previous owner’s server name.

Thanks.

See Uninstall Plex Media Server | Plex Support