10 ILCS 5/5-36
In the event that the voters of any city, village or incorporated town (in any county having a population of 500,000 or more) which has adopted Articles 6, 14 and 18 of this Act (or the Act of which they are a continuation) shall reject the city election law as provided by said Article 6, it shall not be necessary for the registered voters of said city, so rejecting the city election law to register again under the provisions of this Article 5 unless they are not registered under the 1961 and 1962 re-registration provisions.
Within twenty-four hours after the Circuit Judge has entered his order declaring Articles 6, 14 and 18 of this Act rejected by the voters of any city, village, or incorporated town, it shall be the duty of the Board of Election Commissioners formerly having jurisdiction over elections held in such city, village or incorporated town to turn over to the County Clerk the original and duplicate registration cards of all persons affected by the rejection of the city election law in said city, village or incorporated town; the said Board of Election Commissioners shall also turn over to the County Clerk all forms, papers and other instruments pertaining to the registration and election of voters within the said city, village or incorporated town that rejected the city election law, and they shall also cause to be delivered to the clerk of any such city, village or incorporated town that rejected the city election law, all booths and ballot boxes formerly used in conducting elections in said city, village or incorporated town.
The original registration cards of the voters turned over to the County Clerk by the Board of Election Commissioners shall be placed in a master file together with the registration cards of all voters who previously registered under the provisions of this Article 5 and said cards shall then become part of the official registration record for the county in which this Article 5 is in effect.
The duplicate cards shall be arranged in precinct order and shall be retained in the office of the county clerk for use in conducting State, county and township elections. The said duplicate cards shall become part of the official registration record for the county in which this Article 5 is in effect.
10 ILCS 5/5-36