I have purchased my SwissPass Flex via Klook. I have also bought Eurail Pass which also allows free train travels in Switzerland. But how do i get this SwissPass being recognised or registered in SBB site for various tickets bookings. For example, I would like to reserve seat for Lucern-Interlaken, Interlaken-Zermatt, St Moritz-Tirano, etc but there is only selection for “full fare” or “half fare” or only regional discounts cards. So, how do i reserve my seats???