Wholesaling Seller Financed Properties

[Will Clark]

So I have been wholesaling in the Nashville / Middle TN area for about 4 months now, and everything is going well. I have done traditional cash sales and one "subject to" deal. However, I am getting more interested in seller financed deals and things are still murky to me on how to wholesale them, especially when there is already a mortgage in place. Is it as simple as negotiating a seller financed situation that makes sense (EX. Seller agrees to $600 a month for 20 years, but I know market rent is 1200), and then assigning all of my rights in the contract to another investor?     

What happens when there is already a current mortgage on the property? Would it be the same process except the seller still has to pay the mortgage every month after we pay them?