You should file Form IL-1040-X, Amended Individual Income Tax Return, if you need to change a previously filed Form IL-1040, Individual Income Tax Return, due to a change that affects items used to figure your Illinois net income or credits.
Your change can occur from a state change or a federal change, i.e.,
- an amendment of your federal income tax return,
- an adjustment made by the Internal Revenue Service (IRS), or
- any other recomputation or redetermination.
You should file Form IL-1040-X only after you have filed a processable Illinois Income Tax return. You must file a separate Form IL-1040-X for each tax year you wish to change. Do not file another Form IL-1040 with “amended” figures to change your originally filed Form IL-1040.
NOTE: Do not file Form IL-1040-X if you are only changing your name, address, or Social Security number. Instead, forward this information to the address provided under ‘‘What if I need assistance?’’.
For more information, please see the instructions for IL-1040-X listed on their website, http://www.revenue.state.il.us/TaxForms/Individual.htm.