If you didn't file your return, double check that the amount in box 16 and 17 from your W-2 were entered correctly. Log in to your account Select Federal from the left menu. Go to Wages and Income. Select Edit next to your W-2.If you already submitted, wait until the IRS either accepts or rejects your return. If the IRS rejects the return you can make the changes and re-submit your return. If the IRS accepts the return, wait until the return has been fully processed and then amend the return.Make sure you need to amend your return before you start.Here are some common reasons why you might owe the state : Your income increased. You didn't have enough state tax withheld from your paychecks. You lost a dependent. You changed your filing status. To amend your 2020 return:1.Log in to your account.2.Scroll down to Your tax return & documents (you may need to select Show), select 2020 and then Amend (change) return.3.Select Amend using TurboTax Online.4 Follow the instructions. Don't worry if your refund changes to $0. This is normal on amended returns.5.You can e-file your 2020 amended federal tax return, but most states require amendments to be printed and filed by mail.