How Exactly Does A Subject To Work?

[Terry Maher]

I understand conceptually what a 'subject to' contract is but i have a question about how to structure it.  I know as an investor you take over the seller's existing mortgage (though not the loan) payments for a period of time, such as while the rehab is being completed.  But i have also heard deals where you can offer the seller a small down payment and they continue to make their own payments.   Is that true, or is just better to agree to assume the payments and then cash the seller out at closing?  Thank you.