Deferment of graduation is not encouraged. You should prepare your course plan in consultation with your exchange coordinator, academic advisor, or programme leader at City University of Hong Kong to ensure that the credits you earn from the target overseas university can be transferred back to CityUHK. This will help you graduate on time.
Normally, graduating students receive the CityUHK official transcript in July. If you go for an exchange in the last semester of your final year, you will receive your CityUHK official transcript in October. Nevertheless, you will still be invited to attend the College Commencement in June.