In the US, IRS tax things are different. Your agreement to work for an employer is a private thing. You only include the IRS in it when you fill out and sign the Form W-4. To avoid making it a IRS thing, fill out your name and address and SSN as usual. Then fill out the other lines with "n-a." Sign it "non-assumpsit, (Your Signature)." Non-assumpsit means "no contract." Since the Form W-4 is an IRS form, this means that you are not contracting with the IRS to give some of your money to them, even though the form might go to them through your employer. Update your employer with a new Form W-4, and gently require him to stop withholding. You may have to sue him for wages he withholds following your Form W-4 update.