The IRS does not allow you to e-file an amended return, so your only option is going to be to prepare, print, and mail the amended return.
If you did not file your original return through our website, you can go to the IRS website (www.irs.gov) and download Form 1040X to manually prepare an amended return. Or you can prepare your amended return through our website by entering your tax information again. When you reach the Filing Method screen, choose "No" to the question that asks if you want to e-file your return. Once you reach the Check Status/Print Tax Return screen be sure that your federal return entered on our website matches your original return that you e-filed or mailed. Then you can select the option to amend your return.
We recommend that you do not amend your tax return until after you have received your refund or paid the taxes you owe from your original return you filed. The IRS will often automatically make a correction to your tax return for missing or incorrect W-2 (W2) or 1099 forms. You do not need to amend your federal tax return if the IRS corrects the error on your tax return when they process your original tax return. You will receive an IRS notice explaining the adjustment or asking for additional forms for documentation.