If your change results in a balance due to the IRS, you will need to file an Amended Return (1040X).
You won't be able to amend your tax return until the IRS releases the 1040-X Amendment form for 2019. The IRS estimate for issuing the 1040X form is mid February.
Additionally, make sure that your 2019 return was accepted in TurboTax Online or paper-filed through the mail.
To prepare an amended return through TurboTax, follow these steps:
Do you need to file the amended return if the correction to the W2 results in a small addition to your refund? Can you decide not to file the amended return because the effort to do so will greatly exceed the benefit to you?