What is Form 1040X?
IRS Form 1040X: Amended U.S. Individual Income Tax Return is used to make corrections or changes to a return that has already been accepted by – or mailed to – the IRS.
TurboTax supports Form 1040X, which means you can use TurboTax to amend your return.
1040X is typically the last form to be finalized by the IRS; historically, it doesn't become available until mid-February, after the IRS has completed processing the enormous backlog of early-filed returns.