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 on the corner. The IRS does not allow you to take it back.
If you left out a W-2, a 1099G, 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 e-file or 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.
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
But wait until your return has been fully processed before you try to amend.
Wait until your original return has been fully processed before you amend, and make sure you have saved a pdf of the original return before you amend. (If you do not save it as a pdf, the amended return will overwrite the original, and the original will be lost forever)
See this TurboTax support FAQ for amending a tax return -
CURRENT YEAR
Do not expect quick results from amending. It can take four months or more for the IRS to process an amended return.
You can watch for information here:
https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1
If you are getting a refund, wait to get it. If you owe money, you can file the amended once the return is processed.
Be sure to include any refund or money paid on your amended return.
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