Restore Apple Watch (v.3) & Remove Store Demo / Retail Mode?

Apple Store & authorized resellers demo watches are locked down and Apple is the only ones which can clear the firmware. If you bought the watch at a store closing auction take your paperwork and watch to the Apple Store to see if they can send it in to be cleared.

Posting for those that stumble upon this: I was able to reset a series 6 in retail/demo mode by triple tapping the “passcode” option in the settings app with two fingers (tap both fingers at the same time). Doing so opens a secret menu in which a factory reset can be performed.