There are several different scams out there
the most popular is to get the owners to pay $7500 to challenge the validity of their mortgage in hopes it will be deemed invalid. If they are successful (1% of the time) then the owners agree to a new mortgage at 2% and market value with the company who gets the old mortgage extinguished being the note holder.
Another tactic is to get the owner to pay $$ to someone to try to negotiate a loan modification or short sale. The short sale requires that they move. The loan mod does not.
Either way, there are better ways to make money with real estate.
As Jack Miller used to say, if everyone else ZIGS, you need to ZAG! Don’t follow the crowd.