To claim a refund, you must file an amended return within 3 years after the date you filed your original return or 2 years after the date you paid the tax. This article includes stepbystep instructions for when and how to amend your tax return using Form 1040X.The additional time, provided in Notice 202321, to file an amended return is automatic. How do I amend my state tax return? I received a letter from IRS stating that I owe money. It was for the year 2019. The Where's my refund? Tool has the most up to date information available about a taxpayer's refund status. Remember to assemble all the paperwork that isn't necessarily standard tax documents, such as confirmation letters for charitable donations. 515 N Flagler Dr Ste P300, West Palm Beach FL 33401-4326.