Change of last name

Your commune should be able to tell you everything that you need to know, not least because they have access to all the current rules on the subject.
Belgium doesn't allow name changes lightly, although I imagine that reverting to your family name of birth, adjusting your name so that it is more easily rendered in French or Dutch, splitting a single name into fore and family names, or dropping part of an hyphenated family name might be more acceptable than just a desire to change your family name.

As Becasse states above, your commune is the place to ask.

Hi, we're you able to do the name change, if so can you please update what was the procedure. I am also on the same boat and my commune is giving hard time about this.