I'll be visiting Switzerland in September with a Swiss Pass, which is also said to cover rail travel to & from Chamonix, France. How does one actually accomplish that trip, since I understand that the French trains require seat reservations? When I travel from Switzerland to Chamonix, do I need to have a reservation for the French portion? How about when I return from Chamonix to Switzerland? Do I have to purchase a reservation or some sort of ticket in Chamonix in order to ride back to Switzerland with the Swiss Pass?