If you incorrectly claimed certain expenses to itemize your deductions or you accidentally included or left out a dependent, you should file an amended return to correct the errors. This could prevent problems later, like notices or an IRS audit.
If you need to make a change or adjustment on a return already filed, you can file an amended return. Use Form 1040-X, Amended U.S. Individual Income Tax Return, and follow the instructions.
But, one thing is clear: Unlike an original Form 1040 – 90% of which are e-filed – amended returns are processed by an actual person at the IRS. That means the IRS doesn't automatically accept amended returns. However, the IRS won't open an audit (or, “examination”) simply because you file an amended return.