As well as defining avoid areas to modify a route, you can drag a route to a new position.
Do this by simply left-clicking on the route, and dragging. As you drag, MapPoint will draw a dotted line connecting the route to the mouse position:

A route being dragged
Release the mouse button to insert a new waypoint at the mouse position. MapPoint will automatically calculate a new “dragged” route that goes through this waypoint:
The new waypoint will be named after a neighboring location (e.g. a street). Although the drag process really only works by inserting a new waypoint, it is an effective way of modifying a route to incorporate personal knowledge – e.g. if you know you want to avoid a city center.

