The Amended U.S. Individual Tax Return, commonly known by its number (Form 1040X), is used to make corrections on Form 1040, Form 1040A, and Form 1040EZ tax returns that have been previously filed. Generally for a tax refund, this form must be filed within 3 years after the date that the original version was filed, or within 2 years after the date that the tax was paid, whichever is later. For a 1040X based on a bad debt or worthless security, it must be filed within 7 years after the due date of the original version. A 1040X that is filed immediately before the due date of the original version is considered "on time". Certain "financial timing" type changes cannot simply be made with the 1040X, and must be requested through the much more complicated form 3115 "Change of Accounting Method". The least obvious (and most common!) example of such a restricted change is in correcting past years business or rental depreciation. Beyond that, form 3115 also lists over 50 other specific change types. Many of those include classic bookkeeping concerns, such as when to recognize revenue and expenses. Receiving a response or refund and perhaps debit from the IRS for forms 1040X take substantially longer than a simple 1040A or 1040EZ. This is because all 1040X forms must be processed manually.