Deferring your program (putting off starting it) is only for commencing undergraduate students. It's not an option if you've already completed one or more semesters/terms of study.
If you are a new student wishing to defer your program, please visit the Getting Started site.
If you've completed one or more semesters/terms, and you need to take a break from your studies, you can apply for program leave. Program leave is available for up to one year, more in very exceptional circumstances.
For further information, visit the Program leave page.