Form 1040X is the Amended U.S. Individual Income Tax Return, according to the Internal Revenue Service. Taxpayers use the form to correct or change information on their original tax returns, such as filing status, deductions, credits or reported income.
Taxpayers typically must file Form 1040X for credits or refunds within 36 months after filing their original returns, including extensions, or within 24 months from their tax payment date, whichever is later, notes the IRS. It takes up to three weeks before the amended return appears in the agency's system, and up to 16 weeks for the agency to process the amended return. Three weeks after submitting Form 1040X, taxpayers can track the status of their returns as received, adjusted or completed, using the IRS online tool or calling the agency's toll-free number.