(735 ILCS 5/3-106) (from Ch. 110, par. 3-106)
    Sec. 3-106. Appearance of defendants. In any action to review any final decision of any administrative agency, the agency shall appear by filing an answer consisting of a record of the proceedings had before it, or a written motion in the cause or a written appearance. All other defendants desiring to appear shall appear by filing a written appearance. Every appearance shall be filed within the time fixed by rule of the Supreme Court, and shall state with particularity an address where service of notices or papers may be made upon the defendant so appearing, or his or her attorney.
(Source: P.A. 88-1.)