Often times you correct it with more paper work. One year, my foreign tax deduction didn’t get filed for some reason (I was doing my own taxes by hand and sending in the forms), so I was hit with a huge tax bill of $30k or so. Then I found out I handled my non-resident wife wrong, so amend 1040X wait for ITIN, etc…it was kind of a mess. I wound up ahead, the IRS owing me instead. They were quite courteous about it on the phone.