35 ILCS 200/16-30
In counties with less than 3,000,000 inhabitants, the board of review may meet at times it deems necessary for supervising and directing the clerk in the duties prescribed in this Article, and shall meet on or before the first Monday each June to revise the assessment of property. At the meeting, the board of review upon application of any taxpayer or upon its own motion may revise the entire assessment of any taxpayer or any part of the assessment as appears to it to be just. The assessment of the property of any person shall not be increased unless that person or his or her agent first has been notified in writing at the address that appears on the assessment books, and been given an opportunity to be heard. The meeting may be recessed as necessary.
35 ILCS 200/16-30