Seller Financing to Traditional Financing Question

Hello all!

I have a question about a seller financing deal I am structuring. There are 2 properties for sale which I purchased. Total purchase price of 325k (115k and 210k). 5 year balloon, 6% IR, 40K down. With the amortization schedule we are following, on year 5 when the balloon is due I will have 17k of equity from the P&I monthly payments, along with 40K from the downpayment, for a total of 57k. These are commercial properties, so assuming I need 30% down, roughly $97.5k for a traditional downpayment financing. I can come up with the missing $40,500, but how do I get access to the 57k of equity I have built in the property as a equity to acquire traditional financing and pay off the sellers note?