Do not file another Form IL-1040 to make changes to a previously filed Form IL-1040. You must file Form IL-1040-X, along with proper supporting documentation, for both corrected and amended returns.Change amendment may be filed online. Non-expedited service will be reviewed within 10 days of submission. Amendments shall be read in full on three different days in each house and reproduced before the vote is taken on final passage. To file online, go to the Illinois LLC Amendment page and click "file" at the bottom of the page. Enter your Illinois filing number in the search box. If the change(s) made to the taxpayer's federal return affects the Illinois return, the taxpayer must complete form IL-1040-X. Below is an overview of constitutional amendment processes in the 50 states. I discuss the various possible ways of amending state constitutions.