When you wish to terminate your tenancy contract you need to fill-in a termination form. Please bear in mind that according to the tenancy contract, which you have signed when moving in, you have the following terms of notice:
6 weeks until the 1st of a given month
8 weeks until the 15th of a given month
Be aware that if you have a contract from August 1st 2008 or later you have to leave your room 7 work days before the termination date.