How to handle Mortgage??

[Cameron Ellis]

I'm usually finding deals that are owned free and clear, but today I came across a property that has been on the MLS 1028 days, my first thought is the seller should defiantly be motivated now! And in fact, he is.. The gentleman a father and law passed and since then the house has been listed for sale. They are currently taking over the payments and they want out! APV is 94-101k I offered them 45k. And their willing to sale, only problem this is my first time dealing with a property with a mortgage and also a real estate agent. This home is in a great buy and hold area and I know it will move fast. How do I get the agent to drop their contract and pay the remaining balance of the mortgage off at closing?