How to amend? I received a unexpected 1099-INT form in the mail. I'm not seeing the option to amend my 2020 return after being accepted. Will this delay my refund also?

[DoninGA]

If the return is accepted you will have to amend your original tax return. An amended return, Form 1040X, can only be printed and mailed to the IRS if the original tax return was not e-filed. The IRS will take up to 16 weeks or longer to process an amended tax return.

Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.

See this TurboTax support FAQ on amending a tax return originally completed and filed using the 2020 TurboTax online editions - https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-turbotax-online-return/01/27577

The IRS Form 1040-X for amending a 2020 tax return is scheduled to be available on 02/26/2021 (subject to change)

[SteamTrain]

If you e-file was accepted and you need to amend?

..the expected 1040X date Might have been moved waaaaaay back later.........The list I just accessed ?

Form 1040X, Amended U.S. Individual Income Tax Return.....03/25/2021.......03/25/2021

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Thus...don't rush it....and never again try to file early....March is soon enough.