Hawaii Revised Statutes Division 1. Government § 88-75

(a) Under rules the board of trustees may adopt, upon application of a member in service or on leave without pay, or the person appointed by the family court as guardian of an incapacitated member, any member who has ten or more years of credited service shall be retired by the system on an ordinary disability retirement allowance if the medical board or other entity designated by the board of trustees, after a medical examination of the member, certifies that:

(b) Upon approval by the system, the member shall be eligible to receive an ordinary disability retirement benefit no earlier than thirty days from the date the application was filed or the date the member terminated service, whichever is later. Retirement shall be effective on the first day of a month, except for the month of December when retirement on the first or last day of the month shall be allowed. A member whose application for an ordinary disability retirement allowance is approved by the system while the member is still in service may terminate service and retire at any time following the approval; provided that retirement shall become effective on the first day of the month following the month the applicant terminates employment or goes off the payroll, except for the month of December when retirement on the first or last day of the month shall be allowed.