Rectify Through Revised Return Before Processing of IT Return by the IT Department In case the return has not been processed by the income tax department and you have noticed the mistake, you can file revised return. The revised return can be filed within two years from the end of financial year. In case the return is filed online, then revised return can be filed online and for manual return, revised return needs to be filed manually. Revised return must have the acknowledgment number of original return filed by the taxpayer. The original return must have been filed before due date i.e. 31st July 2011 for individual taxpayers not required to get accounts audited by CA. Return can be revised any number of time during time limit, return last revised will be treated as valid return and all earlier will become invalid returns.