How do I make changes to my return
If you discover that an error was made on your return after it
was filed or if your federal return was adjusted by the Internal
Revenue Service, you should file an amended Illinois return promptly
using
IL-1040-X,
Amended Individual Income Tax Return. If you are filing the
IL-1040-X due to a federal change, you cannot file the IL-1040-X
until you receive notification from the federal showing it was accepted.
For more information, refer to the
IL-1040-X Instructions
