If I have a 2nd class Swiss Travel Pass, and I’m traveling from Zurich to Bern,
and I choose to purchase a round-trip 1st class upgrade, on a Point-to-Point Upgrade,
(not a Day Upgrade)
my question is:
Do I need to specify a time for my return journey?
Or
do I not need to specify a time, and can I take any train on the same route as my outbound journey on the same day?