Hi @Fay
Yes, in this case it's possible.
You can find the answer here (under terms and conditions):
"Where a train is cancelled or delayed or a route is closed, you may use the next connection with confirmation from the ticket inspector or sales agent."
If you have already purchased a new ticket, please fill in the refund form online:
https://www.sbb.ch/en/travelcards-and-tickets/buying-options/refund-request.html
Kind regards
SandraI