One or two weeks before you leave Belgium, you must deregister as a resident in Belgium. In Antwerp, this can be done by means of an e-service on the website or at the local authority. You can also e-mail your HR officer to request the Model 8 for you and fill in the letter of attorney. When you have left Belgium, please send back your identy card to the District House.
It is important to deregister. If you don’t, you run the risk of having problems with your visa application on your next visit and you may even be denied entry to Belgium.