Speak to an attorney. There is nothing illegal or even terribly complicated here EXCEPT that the way you would do this is different if it was a sole proprietorship vs. an LLC vs. a corporation (including an S-corp): you want the forms and formalities to be done correctly. You also want the lawyer to help you plan how to take over bank accounts and utilities; if there are any important contracts (e.g. leases or contracts with customers), you need the attorney to review them and make sure you can take them over (some contracts or leases state that they may *not* be taken over by another person); discuss what happens with any accounts receivable (does the old owner get money for sales made while he owned the business) and incorporate that into an agreement; etc. This is not legally complicated--every individual thing to do is straightforward--but there are lots of "parts" to doing this right; if it's worth taking over the business, it's worth consulting with an attorney to make sure it's done correctly.