An amended return is a tax return submitted to the tax authorities by a taxpayer to correct errors or make changes to a previously filed tax return. The need for an amended return can arise for various reasons, such as the discovery of mistakes, receipt of additional income information, changes in deductions, or adjustments to tax credits.

Key points about amended returns include:

1. **Form used:** In the United States, individuals typically use Form 1040X to file an amended return. For businesses, various forms may be used depending on the type of entity (e.g., Form 1120X for corporations).

2. **Timing:** Amended returns are usually filed after the original tax return has been submitted. There is generally a specific time limit for filing an amended return, typically within three years from the date of the original return or within two years from the date the tax was paid, whichever is later.

3. **Reasons for filing:** Common reasons for filing an amended return include correcting errors in income reporting, changing filing status, updating the number of dependents, claiming additional tax credits, or making adjustments to deductions.

4. **Amending state returns:** If a taxpayer needs to amend a federal tax return, it’s often necessary to amend the corresponding state tax return as well. State tax agencies usually have their own procedures and forms for filing amended returns.

5. **Mail submission:** Amended returns are typically filed by mail, as electronic filing is generally not available for amended returns.

6. **Documentation:** Taxpayers filing an amended return should include any necessary supporting documentation, such as additional forms, schedules, or explanations for the changes being made.

7. **Refund or additional tax:** Depending on the changes made, filing an amended return can result in either a refund or an additional tax liability. If a refund is due, it may take some time for the tax authorities to process the amended return and issue the refund.

It’s important for taxpayers to carefully review their original tax return and the changes they intend to make before filing an amended return. If uncertain about the process or the impact of the changes, seeking guidance from a tax professional is advisable. Additionally, tax laws and regulations may change, so it’s important to refer to the most current information provided by tax authorities.