Why it matters
An amended return can recover a missed deduction or correct a notice, but it can also increase the tax. The form needs the original return and the document that supports the change.
Example
A client receives a corrected Form 1099 after filing. The preparer prepares Form 1040-X with the corrected income, explains the change and files it with the supporting form.
Related terms
Questions about Form 1040-X
How long does a taxpayer have to file Form 1040-X?
The deadline depends on the reason for the amendment and the original return. A claim for a refund generally has a limited period from the filing date or the payment date, so check the current instructions.
Can Form 1040-X be filed electronically?
Electronic filing is available for many amended returns, but not every situation. Check the current IRS guidance and the tax software before choosing a method.