How do I amend my New York state tax return?

Purpose of Form IT-201-X
If after filing your New York State income tax return you realize you have made an error or if the Internal Revenue Service (IRS) makes changes to your federal return, you must file an amended New York State return to correct the error or report the changes.

Use Form IT-201-X if your original return was Form IT-100,  Form IT-200, or Form IT-201. Use Form IT-203-X to amend nonresident and part-year resident Form IT-203 or if you mistakenly filed Form IT-100, IT-200, or IT-201, but you were a nonresident or part-year resident.

Do not use Form IT-201-X to report a net operating loss carryback, to protest a paid assessment which was based on a statement of audit changes or to file a protective claim; use Form IT-113-X, Claim for Credit or Refund of Personal Income Tax. However, if you are reporting any of the above and some other change to your state return, you must file Form IT-201-X or the appropriate amended return, showing all changes; do not use Form IT-113-X in this case.

If you receive an assessment from the Tax Department, do not file an amended return strictly to protest the assessment.  Follow the instructions you receive with the assessment.

When to File an Amended Return
File Form IT-201-X after you have filed your original return.  Generally, Form IT-201-X must be filed within three years of the date the original return was filed or within two years of the date the tax was paid, whichever is later. A return filed early is considered filed on the due date.

If you file an amended federal return to make changes to your federal income, tax preference items, total taxable amount, capital gain or ordinary income portion of a lump-sum distribution, the amount of your earned income credit or credit for child and dependent care expenses, or the amount of your foreign tax credit affecting the computation of the resident credit for taxes paid to a province of Canada, you must also file an amended New York State return within 90 days of the date you amend your federal return. 

If the IRS changes any of these items, you must report these changes to the New York State Tax Department on an amended return within 90 days of the IRS final determination. If you do not agree with the IRS determination, you must still file an amended state return indicating your disagreement. To report changes for a tax year prior to 1988, use Form IT-115, Report of Federal Changes.

To find the current amended forms check the NY website.

NY amended returns can be e-filed within the current year.  Prior year amended returns must be printed and mailed for filing.