Certain changes can be made after your EIN / Tax ID is assigned. You will need to do this by calling the IRS / EIN line for changes at 1-800-829-4933. These changes include fixing the business name, business address, or the date that the busines started. You may be required to hand write a letter to the IRS describing the required changes, and you will be directed by the IRS staff on the steps you must take.