Ill. Admin. Code tit. 44, § 2600.305
c) Bidder Submissions
d) Public Notice
e) Pre-Bid Conference
A pre-bid conference may be conducted to enhance understanding of the procurement requirements. The pre-bid conference shall be announced as a part of the Invitation for Bids notice. The conference may be designated as "attendance mandatory" or "attendance optional". The conference should be held long enough after the Invitation for Bids has been issued to allow bidders to become familiar with it, but sufficiently before bid opening to allow consideration of the conference results in preparing their bids. Nothing stated at the pre-bid conference shall change the Invitation for Bids unless a change is made by written amendment to the Invitation for Bids. Amendments shall be supplied to all those prospective bidders known to have received an Invitation for Bids. If the conference is mandatory, the amendment shall be supplied to attendees only.
f) Amendments to Invitations for Bids
g) Pre-Opening Modification or Withdrawal of Bids
h) Receipt, Opening and Recording of Bids
i) Bid Evaluation and Award
2) Responsiveness. A bid must conform in all material respects to the Invitation for Bids.