Ill. Admin. Code tit. 44, § 1500.2038
a) General
Corrections to bids, proposals or other procurement processes are allowed, but only to the extent not contrary to the best interest of the State or the fair treatment of other bidders.
b) Mistakes Discovered Before Opening
A vendor may correct mistakes discovered before the time and date set for opening by withdrawing or correcting as provided in this Section.
c) Confirmation of Mistake
When the Procurement Officer knows or has reason to conclude that a mistake has been made, such officer shall request the vendor to confirm the information. Situations in which confirmation should be requested include obvious or apparent errors on the face of the document or a price unreasonably lower than the others submitted. If the vendor alleges a mistake, the bid or proposal may be corrected or withdrawn if the conditions set forth in this Section, as applicable, are met.
d) Mistakes in Bids Discovered After Opening but Before Award
1) Minor informalities. A minor informality or irregularity is one that is a matter of form or pertains to some immaterial or inconsequential defect or variation of a bid from the exact requirement of the Invitation for Bids, the correction or waiver of which would not be prejudicial to the State (i.e., the effect on price, quality, quantity, delivery, or contractual conditions is negligible). The Procurement Officer shall waive such informalities or allow the bidder to correct them depending on which is in the best interest of the State. Examples of minor informalities as to form include the failure of a bidder to:
B) acknowledge receipt of an amendment to the Invitation for Bids, but only if:
3) Mistakes Where Intended Correct Bid Is Not Evident. A bidder may be permitted to withdraw a low bid if:
This subsection (d) sets forth procedures to be applied in situations in which mistakes in bids are discovered after the time and date set for bid opening but before award.
e) Mistakes in Proposals Discovered After Receipt, but Before Award
3) Correction of Mistakes. If discussions are not held or if the best and final offers upon which award will be made have been received, mistakes may be corrected and the intended correct offer considered only if:
4) Withdrawal of Proposals. If discussions are not held, or if the best and final offers upon which award will be made have been received, the offeror may be permitted to withdraw the proposal if:
This subsection (e) sets forth procedures to be applied in four situations in which mistakes in proposals are discovered after receipt of proposals but before award.
f) Mistakes Discovered After Award
Mistakes shall not be corrected after award of the contract except where the Procurement Officer finds it would be unconscionable (e.g., if the mistake resulted in a windfall to the State) not to allow the mistake to be corrected.
g) Determinations Required
When a proposal is corrected or withdrawn, or correction or withdrawal is denied, a written determination shall be prepared showing that relief was granted or denied in accordance with this Part. The Procurement Officer shall prepare the determination.