Sole Proprietorship. Write to us at the address where you filed your return, informing the Internal Revenue Service (IRS) of the name change.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. 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. Are you planning an IRS business name change? You may not need a new EIN. If you've changed your legal or business name, you might need to notify the IRS or the Social Security Administration (SSA). If your business has a new physical address, or the responsible party for the business has changed, then you need to file Form 8822B. Follow our stepbystep guide covering how to properly amend your business name, to stay compliant with all state and local laws.