I am certainly not trying to discredit you,and am responding moreso to provoke discussion. I do not have the complete answer here. I'd rather keep this public than private as it is clear that you can speak intelligently so let's keep the discussion going. As I said, i do not have the answer.
That being said, I can only sell a house if I have complete ownership. The sheriff sale is initiated by someone who has proved in the courts that they have a right to take back the house and they have done so. How then can it revert to the original owner if nobody buys it at sheriff sale. What legal instrument conveyed the property back to the original owner?
Robyn is correct below. There may be times when the sale is postpone the same day and will sell at a later date and time. Auction homes can change status few hours before the sale actually happens, so if there is a home you are interested in then make sure you call the trustee services the same day and every hour.