Hello Ghussafee22
Please kindly note, this platform is run by SBB customers for other SBB customers, and not by the SBB customer service itself. Nevertheless, we are able to answer your question 🙂
See the option for class upgrades with the Saver Day Pass on this website:
https://sbb-tickets.cc/en/tickets-offers/tickets/point-to-point-tickets-switzerland/class-upgrades-supersaver-class-upgrades/class-upgrade.html
Please kindly note: Supersaver Class Upgrades are possible holding a Saver Day Pass. However, this type of upgrade cannnot be combined with Supersaver tickets.
Kind regards,
Roland