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. If you've changed your legal or business name, you might need to notify the IRS or the Social Security Administration (SSA). This file is a template for an IRS cover letter informing the IRS of a company name change. Are you planning an IRS business name change? You may not need a new EIN. 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. The City of Oakland has developed this tool to help business owners estimate their City of Oakland Business License Tax. Unable to determine if the taxpayer is changing their name,, Do not update the taxpayer's name.