I didn't change my hours to part time ...just full time with sick leave forms to work less (unpaid as no leave left) and gradually increased my work hours with a return to work plan. Surprisingly I managed pretty much the same workload in less hours. (Sadly not same money) My certificate just included what I could do, not what I couldn't.
https://www.fairwork.gov.au/leave/sick-and-carers-leavehttp://employsure.com.au/blog/management-of-non-work-related-injuriesillnesses-employers-health-and-safety-obligations-relating-to-employees-injured-outside-of-work/