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:
You can check the status of your amended return here but allow 3 weeks after filing for it to show up:
Did you e-file already? If you e-filed it is too late and you cannot cancel it. If you did not e-file then you do not have to file the return until you correct your mistakes -- or you can simply abandon the account and go elsewhere if you choose to.
You cannot change or add anything on the return that you just e-filed, nor can you stop it. It is too late, just like when you put an envelope in a US mailbox
If you left out a W-2, or a dependent, or a 1099 etc…DO NOT change your return while it is pending. The changes will go nowhere.
Now you have to wait until the IRS either rejects or accepts your return. If your return is rejected, you will be able to go into your account and make the necessary changes to your tax return and re-submit your return.
If the IRS accepts your return, however, then you have to wait longer until it has been fully processed and you have received your refund. THEN you can prepare an amended tax return and mail it in. You have to be able to work from that return exactly the way it was when it was e-filed originally. You will need to use a form called a 1040X. You cannot e-file an amended return. They have to be mailed, and it takes at least 2-4 months for the IRS to process an amended return. Meanwhile, DO NOT go in and start changing anything on your return in the system, or you will make a mess for yourself. Sit tight and wait until you see what the IRS does with the return you just e-filed