Students and staff can change their contact and address details on the NWU DIY Services web page. You will find a link to the DIY Services in the purple banner at the bottom of the University web pages. Once you have clicked on the link, which I also attached below, choose the status that applies to you e.g. Undergraduate Students to see the services provided to that group.
Please read the How-To-Guide under the service for more information. It also contains the contact details of the person responsible for this specific service.