A written lease for a specific period may, in principle, not be terminated early. The model lease from Kotweb provides both parties the option to terminate the lease early if you terminate your studies early, during the current academic year. A 1 month notice period is then required. The termination of your studies must be official. That is to say that you must present the landlord with a certificate of de-registration from your educational institution. Furthermore, you must cease all studies in the same city. (so not stopping at school A in Antwerp and then going to study at school B in Antwerp). If a new tenant is found during the notice period, the existing model lease will be dissolved at the time that the new lease takes effect. The property owner can no longer require termination compensation from the original tenant.
Should any problems arise, as a student at one of Antwerp's higher educational institutions, you can always ask for help from Kotweb. Kotweb can mediate with the landlord and possibly help find another student who wants to take the room over. Sometimes students want to change their accommodation or would like to rent a room for a shorter period, e.g. during an internship. The landlord must of course agree to this.