How to modify a route from the route summary menu?

Accessing the "Menu" selection:

In the menu, tap on the "Route" button which will take you into route summary screen:

Here, you have several options:

Cancel route - This will cancel the current route
Route options - Here you can select various options:
Demonstrate - make a demonstration playback of the current route
Show on map - this will show the entire route on the map
Change start point
Change destination
Travel via - set a waypoint which you want to travel through
Save route - save route for later use
Avoid - here you can avoid motorways, toll roads, ferry lines
Poi On Route - Search for POIs which are along your current route.