405 ILCS 5/3-801
A respondent may request admission as an informal or voluntary recipient at any time prior to an adjudication that he is subject to involuntary admission on an inpatient or outpatient basis. The facility director shall approve such a request unless the facility director determines that the respondent lacks the capacity to consent to informal or voluntary admission or that informal or voluntary admission is clinically inappropriate. The director shall not find that voluntary admission is clinically inappropriate in the absence of a documented history of the respondent's illness and treatment demonstrating that the respondent is unlikely to continue to receive needed treatment following release from informal or voluntary admission and that an order for involuntary admission on an outpatient basis is necessary in order to ensure continuity of treatment outside a mental health facility.
If the facility director approves such a request, the petitioner shall be notified of the request and of his or her right to object thereto, if the petitioner has requested such notification on that individual recipient. The court may dismiss the pending proceedings, but shall consider any objection made by the petitioner, the respondent, or the State's Attorney and may require proof that such dismissal is in the best interest of the respondent and of the public. If voluntary admission is accepted and the petition is dismissed by the court, notice shall be provided to the petitioner, orally and in writing, of his or her right to receive notice of the recipient's discharge pursuant to Section 3-902(d).
405 ILCS 5/3-801