You may discover you made a mistake on your tax return. You can file an amended return if you need to fix an error. You can also amend your tax return to claim a tax credit or deduction. Here are 10 tips from the IRS on amending your return: When to amend. You should amend your tax return if you need to correct filing status, the number of dependents or total income. You should also amend your return to claim tax deductions or tax credits that you did not claim when you filed your original return. The instructions for Form 1040X, Amended U.S. Individual Income Tax Return, list more reasons to amend a return. When NOT to amend. In some cases, you don’t need to amend your tax return. The IRS will make corrections, such as math errors, for you. If you didn’t include a required form or schedule, for example, the IRS will mail you a notice about the missing item.