765 ILCS 205/6
Any plat may be vacated by the owner of the premises at any time before the sale of any lot therein, by a written instrument to which a copy of the plat is attached, declaring it to be vacated. If there are public service facilities in the highways, streets, alleys and other public ways and in easements shown on the plat, the instrument shall reserve to the public body or public utility owning such facilities, the property, rights of way and easements necessary for continuing public service by means of those facilities and for the maintenance, renewal and reconstruction of the same. The instrument shall be approved by the city council or village or county board in the same manner as plats of subdivisions. The instrument shall also be submitted for approval to the Highway Commissioner and to the county engineer or superintendent of highways and to the District Engineer of the Department of Transportation of this State and to the public utility or utilities involved. The council, board, Highway Commissioner, county engineer or superintendent of highways or District Engineer of the Department of Transportation of this State, as the case may be, may reject any instrument that abridges or destroys any public rights in any of its streets and alleys. The instrument shall be executed, acknowledged or proved and recorded or filed in the same manner as plats or subdivisions. Once recorded or filed the instrument operates to destroy the effect of the recording of the plat vacated and to divest all public rights in the streets, alleys and public grounds and all dedications laid out or described in the plat and to render effective any reservation set forth in the instrument as provided in this Section. When lots have been sold the plat may be vacated in the manner provided in this Section by all the owners of lots in the plat joining in the execution of the writing.
765 ILCS 205/6