After you file

If you actually transmitted your tax return then it is too late.

You have *not* actually filed since the IRS will not open e-file until Jan. 27, but if you submitted it to TurboTax then see below (but the IRS does accept some "test batches" early but will not process them):

If you filed, it is like dropping it into the mail - you cannot get it back if accepted by the IRS or state.

To amend your 2019 tax return:

-- First, *wait* to see if your return has been accepted or rejected by the IRS or state. DO NOT do anything until you receive the accept or reject e-mail.

-- If rejected, you can correct and re-send your return.

-- If accepted you should *wait* until your return has been processed and you receive your refund or conformation that any tax due has been paid. (If you file an amended return while you first return is being processed it can cause extended delays for both returns if two returns are in the system at the same time). In addition, if the IRS makes any change on your original return, you might end up having to amend the amendment – a sticky process that can take a year or more).

-- Then you can start the amend process.

-- Amended returns can only be mailed - allow 8-12 weeks - can take up to 16 weeks (4 months) for processing.

See this TurboTax FAQ for help with amending:

https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed

You can check the status of your amended return here but allow 3 weeks after filing for it to show up:
https://www.irs.gov/filing/wheres-my-amended-return