I have always thought that: (a) a patient can withdraw his case, with the tribunal’s consent; and (b) a reference maker can withdraw a discretionary reference, without needing the tribunal’s consent, but cannot withdraw a mandatory reference.
I didn’t think the patient could withdraw a reference at all, as I had interpreted “its case” in rule 17(1)'s “a party may give notice of the withdrawal of its case” as meaning the case of the person who made the application or reference. This is consistent with the wording of rule 17(3) which says: “A party which started a mental health case by making [mandatory reference] may not withdraw its case.” See Withdrawal (MHT).
The tribunal which consented to the patient’s application to withdraw the discretionary reference must have thought differently, i.e. that “its case” in a reference case means the case of the reference maker or of the patient.