225 ILCS 135/105
The Department may investigate the actions of any applicant or any person holding or claiming to hold a license. The Department shall, before revoking, suspending, placing on probation, reprimanding, or taking any other disciplinary action under Section 95 of this Act, at least 30 days prior to the date set for the hearing, (i) notify the accused, in writing, of any charges made and the time and place for the hearing on the charges, (ii) direct him or her to file a written answer to the charges with the Department under oath within 20 days after service of the notice, and (iii) inform the accused that, if he or she fails to answer, default will be taken against him or her or that his or her license or certificate may be suspended, revoked, placed on probationary status, or other disciplinary action taken with regard to the license, including limiting the scope, nature, or extent of his or her practice, as the Department may deem proper. In case the person, after receiving notice, fails to file an answer, his or her license may, in the discretion of the Department, be suspended, revoked, placed on probationary status, or the Department may take whatever disciplinary action considered proper, including limiting the scope, nature, or extent of the person's practice or the imposition of a fine, without a hearing, if the act or acts charged constitute sufficient grounds for such action under this Act. The written notice may be served by personal delivery or certified mail to the licensee's address of record .
225 ILCS 135/105