Sole Proprietorship. Write to us at the address where you filed your return, informing the Internal Revenue Service (IRS) of the name change.Learn how to change your business name with the IRS. 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. If you've changed your legal or business name, you might need to notify the IRS or the Social Security Administration (SSA). 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. An IRS LLC name change is perhaps the easiest one to perform. All you need to do is put down a name change statement on your company's tax return. I am a business owner and my personal legal name changed; how do I update my business records?