You will have to wait and see if your return gets rejected or accepted by the IRS.
Please be aware that the IRS currently won't start processing returns until February 12, 2021.
- If your return will be rejected by the IRS, all you have to do is make changes on your return and refile.
- If your return will be accepted by the IRS, you have to file an amended return (1040X) to make changes. But you might want to wait until your refund or payment is processed. Please be aware that you can e-file your 2020 amended federal tax return, but most states require amendments to be printed and filed by mail.
Please see FAQ How to amend a tax return for instructions.