A) According to the IRS: Many mistakes are corrected in processing and a letter of explanation is mailed at the time the refund is issued.
If the mistake was not corrected in processing, you need to:
- File an amended or corrected return using Form 1040X (PDF), Amended U.S. Individual Income Tax Return, as soon as possible.
- Include copies of any schedules that have been changed or any Form(s) W-2 (PDF) you did not include.
- If you return the refund check with a letter of explanation, a refund in the correct amount will be issued when the IRS processes the amended return.
- Write “Void” in the endorsement section of the check, and return the check with a letter of explanation to the Service Center where you file your amended return as soon as possible to minimize the interest charges.
- Allow the IRS 8-12 weeks to process the amended return.