How to completely reset Ultimate Facebook settings

I have recently reconfigured my FB page owners, needed to create new app to enable UFB to repost to the pages with brand new owner. However, even with correct App ID and App Secret, UFB fails to recognise the new pages, and insists on the pages available to the previous owner.

I have tried uninstalling and re-installing the plug in, but the damn settings will not reset, and it remembers the previous settings (which do not work).

Where and how do I reset ALL Ultimate Facebook settings, so I can start completely from scratch with configuration??