After you file

This was posted 2 weeks ago - Is 3/17/2022 still the date when the amended 1040X return for 2021 will be functioning in TurboTax? I filed for 2021 already and got a refund but received a LATE 1099B/DIV and have to amend my 2021 return. When can I use TurboTax to file the 1040X for 2021???