If you are filing a current year Form 1065, mark the appropriate name change box on the form: Page 1, Line G, Box 3. Learn how to change your business name with the IRS.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've changed your legal or business name, you might need to notify the IRS or the Social Security Administration (SSA). Find forms, samples and fees for most business entity filings here. 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 namechange letter should clearly state that your business name has changed. Complete and submit an Application to Change Business Name or Address. Fiscal Provisions a.