Hi sharpy1957
Thanks a lot for your question.
Seating reservtions can be purchased either online: Seat reservations in trains and dining cars | SBB or on the SBB Mobile App, choosing the connection and then scrolling down to “view all tickets and reservations” and then “seat reservation”.
For further information, please call our SBB Contact Center (+41 848 44 66 88, available 24/7, CHF 08.08/min).
I wish you a nice day!
EleonoraS