225 ILCS 645/10
The Department may, upon its own motion, and shall, upon the complaint in writing of any person setting forth facts which if proved would constitute grounds under Section 9, investigate the actions of any applicant or any person or persons holding or claiming to hold a license. At least 10 days prior to the date set for hearing the Department shall, before refusing to issue or renew and before revoking a license, notify in writing the applicant for or holder of a license, hereinafter called the respondent, that on the date designated a hearing will be held to determine whether the respondent is privileged to hold such license.
The Director shall, after a hearing, issue an order either issuing, renewing, refusing to issue or renew, reinstating, or revoking the license. Such written notice may be served personally on the respondent, or by registered or certified mail sent to the respondent's business address as shown in his latest notification to the Department.
The Department, over the signature of the Director, may subpoena any person or persons in this State and take testimony orally, by deposition or by exhibit, in the same manner and with the same fees and mileage as prescribed in judicial proceedings in civil cases.
225 ILCS 645/10