Walk to random waypoint

My char. is walking along a set path of waypoints right now. I am trying to make him walk to a random waypoint instead. Anyone know of a solution? Perhaps assign a random.range index for the waypoints? I cant figure it out how to do it.

 // ... increment the wayPointIndex.
                 if(wayPointIndex == patrolWayPoints.Length - 1)
                     wayPointIndex = 0;
 
                 else
                     wayPointIndex++;
             
                 // Reset the timer.
                 patrolTimer = 0;
             }
         }
         else
             // If not near a destination, reset the timer.
             patrolTimer = 0;
 
         // Set the destination to the patrolWayPoint.
         nav.destination = patrolWayPoints[wayPointIndex].position;
     }