You (or the purchaser or transferee) must complete Form CBS-1, Notice of Sale, Purchase, or Transfer of Business Assets. A buysell agreement is a legally binding contract that sets out the terms of how business partners will manage their ownership if one of them leaves.Buying out a business partner is a complicated process. Certified deemed-compliant limited life debt investment entity. Forms on this website are PDFs with fillable fields. Forms should be downloaded to your computer before filling in the fields. How to Write a Real Estate Purchase Agreement.