10 ILCS 5/10-7
Except as otherwise provided in this Code, any person whose name has been presented as a candidate, including nonpartisan and independent candidates, may cause his name to be withdrawn from any such nomination by his request in writing, signed by him and duly acknowledged before an officer qualified to take acknowledgment of deeds, and presented to the principal office or permanent branch office of the Board, the election authority, or the local election official, as the case may be, not later than the date for certification of candidates for the ballot. No name so withdrawn shall be printed upon the ballots under the party appellation or title from which the candidate has withdrawn his name. If such a request for withdrawal is received after the date for certification of the candidates for the ballot, then the votes cast for the withdrawn candidate are invalid and shall not be reported by the election authority. If the name of the same person has been presented as a candidate for 2 or more offices which are incompatible so that the same person could not serve in more than one of such offices if elected, that person must withdraw as a candidate for all but one of such offices within the 5 business days following the last day for petition filing. If he fails to withdraw as a candidate for all but one of such offices within such time, his name shall not be certified, nor printed on the ballot, for any office. However, nothing in this section shall be construed as precluding a judge who is seeking retention in office from also being a candidate for another judicial office. Except as otherwise herein provided, in case the certificate of nomination or petition as provided for in this Article shall contain or exhibit the name of any candidate for any office upon more than one of said certificates or petitions (for the same office), then and in that case the Board or election authority or local election official, as the case may be, shall immediately notify said candidate of said fact and that his name appears unlawfully upon more than one of said certificates or petitions and that within 3 days from the receipt of said notification, said candidate must elect as to which of said political party appellations or groups he desires his name to appear and remain under upon said ballot, and if said candidate refuses, fails or neglects to make such election, then and in that case the Board or election authority or local election official, as the case may be, shall permit the name of said candidate to appear or be printed or placed upon said ballot only under the political party appellation or group appearing on the certificate of nomination or petition, as the case may be, first filed, and shall strike or cause to be stricken the name of said candidate from all certificates of nomination and petitions filed after the first such certificate of nomination or petition.
Whenever the name of a candidate for an office is withdrawn from a new political party petition, it shall constitute a vacancy in nomination for that office which may be filled in accordance with Section 10-11 of this Article; provided, that if the names of all candidates for all offices on a new political party petition are withdrawn or such petition is declared invalid by an electoral board or upon judicial review, no vacancies in nomination for those offices shall exist and the filing of any notice or resolution purporting to fill vacancies in nomination shall have no legal effect.
Whenever the name of an independent candidate for an office is withdrawn or an independent candidate's petition is declared invalid by an electoral board or upon judicial review, no vacancy in nomination for that office shall exist and the filing of any notice or resolution purporting to fill a vacancy in nomination shall have no legal effect.
All certificates of nomination and nomination papers when presented or filed shall be open, under proper regulation, to public inspection, and the State Board of Elections and the several election authorities and local election officials having charge of nomination papers shall preserve the same in their respective offices not less than 6 months.
10 ILCS 5/10-7