I purchased a Glacier Express Ticket with the Excellence Class Special from Brig to Chur. This included a regular point to point ticket for CHF 71.50. I need to get to Chur from Zermatt, and I need to get to Luzern from Chur all the same day. I see that to upgrade to a Saver Day Pass would be an additional CHF 10.50 if you purchased the ticket at the same time. Since I already have the point to point ticket from Brig to Chur, is there a way to upgrade my ticket to a Saver Day Pass by paying just the additional CHF 10.50? Or do I need to buy 2 separate point to point tickets from Zermatt to Brig, and then from Brig to Luzern? Or is there a better way? Thank you!