In base Catan, the rules allow you to play a Knight card before you roll the dice. Obviously, there are no Development Cards in Cities and Knights, and instead there are physical knight tokens.
The rule book doesn't seem to specifically address if you can use your activated Knight token to chase away the Robber on your turn before you roll the dice.
Since the rules do not specifically say you can, and by default the dice roll is usually always required as the first action of your turn, our group agrees to play that you can only use a Knight action after you roll the dice.
Are we missing something in the rules? Does a Catan FAQ somewhere answer this?