Section 8-111. Answer

a. Within thirty days after a copy of the complaint is
  served  upon the respondent by the commission, the respondent shall file
  a  written,  verified  answer  thereto  with  the  commission,  and  the
  commission  shall  cause  a  copy  of  such answer to be served upon the
  complainant and any necessary party.
    b. The respondent shall specifically admit, deny, or explain  each  of
  the  facts  alleged  in  the complaint, unless the respondent is without
  knowledge or information sufficient to form a belief, in which case  the
  respondent shall so state, and such statement shall operate as a denial.
    c.  Any  allegation  in  the  complaint  not  specifically  denied  or
  explained shall be  deemed  admitted  and  shall  be  so  found  by  the
  commission unless good cause to the contrary is shown.
    d. All affirmative defenses shall be stated separately in the answer.
    e. Upon request of the respondent and for good cause shown, the period
  within  which  an  answer  is  required  to  be filed may be extended in
  accordance with the rules of the commission.
    f. Any necessary  party  may  file  with  the  commission  a  written,
  verified  answer to the complaint, and the commission shall cause a copy
  of such answer to be served upon the  complainant,  respondent  and  any
  other necessary party.
    g.  Any  answer filed pursuant to this section may be amended pursuant
  to procedures prescribed by  rule  of  the  commission  by  filing  such
  amended  answer  with the commission and serving a copy thereof upon the
  complainant and any necessary party to the proceeding.