Learn how to change your business name with the IRS. If you are filing a current year Form 1065, mark the appropriate name change box on the form: Page 1, Line G, Box 3.The first step is to file a form called the Certificate of Amendment with the Bureau of Corporations and wait for it to be approved. In order to change your LLC name with the IRS, you'll need to mail them a letter and show proof of the state approving your LLC name change. If you need to change your business name, you will need to file forms with various agencies. Sole proprietorships changing their Legal Name must file updates. I am here to teach you guys how to change your business name. How do I fill this out? To fill out this form, you need to provide the old and new company names, your federal identification number, and contact details. The IRS asks that you send a letter, on company letterhead (if available) providing the name and Social Security Number of the owner(s) of the LLC.