Getting a release letter from an Australian university as an international student to change your course before completing six months may not be guaranteed, as each university has its own policies and procedures. However, it is advisable to contact your university's international student office and discuss your situation with them. Some universities may consider release requests under certain circumstances, such as academic or personal reasons. It's essential to provide a clear explanation and supporting documentation for your request. Keep in mind that the ease of obtaining a release letter can vary, and the decision ultimately rests with the university's policies.