Sub to contract help

[Drew Nelson]

I am pretty familiar with seller finance and was looking for a client we found a home offering that we like the numbers on. I then looked it up and there is a mortgage on it so clearly not a straight seller finance and will be sub to I have been on the list side but never the buy side of sub to can we use a propagated contract or do we need a lawyer to build one. If anyone has one or a great lawyer recommendations I am open