Visit the Bexar County Purchasing Website and go to the Supplier Portal Registration and follow the steps listed. An asset purchase agreement is the legal document that will govern the transfer of ownership of a business's assets from the seller to the buyer.All you need to do is fill out an Application to Update an Existing Certificate of Occupancy to request a name change on the existing certificate of occupancy. An asset purchase agreement (or APA) is a binding document between a buyer and seller for the purchase and sale of a company's assets. Complete list of Texas Comptroller Property Tax Forms and Applications click here. Texas Comptroller Property Tax Publications click here.