Once a return has been submitted electronically, it cannot be stopped and will be transmitted to the IRS and processed. You will receive an acknowledgement from the IRS indicating the acceptance or rejection of your return, generally within 48 hours after they receive it.
If the IRS rejects the return, you can make necessary corrections and resubmit the return electronically for no additional charge (assuming you e-file through the same TaxAct product from which you initiated the return).
If the IRS accepts your return, you will need to file Form 1040X, Amended U.S. Individual Income Tax Return to make any changes. Form 1040X cannot be electronically filed for tax years before 2019; therefore, you will need to print the form and mail it to the IRS.