Remain quiet and professional, and do not engage the passenger.
If you are being insulted, ignore the passenger and proceed to send the passenger to the destination.
However, if the passenger is being violent and your safety is at risk, drive to a safe area with people around to alight your passenger. If the passenger refuses, your safety comes first, get out of your parked car with your keys and call the Police if necessary.
Let us know, if you feel that the passenger is a potential danger to others, through the form below.