the only quick way I found to switch is to hit the return key and then use the scroll to choose.

edit, by the way, Alt, Esc. works on this too. Antoher thing to note. If it is giding you and you were supposed to go off a bit to the right or left, it takes about 30 seconds to recognize that you went out of the way and then like you said, the recalc is pretty quick. One thing is that it is stubburn and sems to want to take me on too many right ald lefts while the route should be straight and then turn right. I wish their system had a litle smart feature or allows fro som feed back.