Complete your amended return as if you are filing the return for the first time. Submit all the forms relevant to the information in your amended return.You must file an amended 2023 New York State return if: • You made an error when you filed your original 2023 New York State income tax return. Amend Form NYC-4S, NYC-3L or NYC-3A, as originally. The court has placed the most commonly used forms on line as a resource. Please be advised that the forms detailed below are intended to be a guide. When you amend—using either Form IT-201-X or Form IT-203-X—it's like filing a new state return. For paper returns, mark the oval labeled "Amended Return. " Complete the new return using the corrected information, as if it were the original return. Complete and sign this form if (1) a tax return preparer filed a Form 1040 series tax return or altered your Form 1040 series tax return.