Can I file an Amended tax return online?
An amended tax return (Form 1040X) must be mailed to IRS at the appropriate Service Center address. And processing of form 1040X takes anywhere from 12-16 weeks. If IRS catches the error before sending you a refund they will make changes to your tax return and write you a letter advising you of your changes, wait to file the F1040X until your original Tax return has been processed.