seat reservation

[chuchu23]

I am going to use an open panorama car at below image time.

I found a screen where I could make a seat reservation.

However, it can not be booked at the time of day.

When you look at the timetable, the open panoramic car comes out that the reservation is compulsory.

I wonder how I can use an open panoramic car.

Please Thank you very much for your reply. 

[NicolasK]

Dear @chuchu23

As already answered a few minutes ago, you can contact the RHB directly (https://www.rhb.ch/en/service-souvenirs/contact)
Unfortunately we have no further information for these trains.

Thank you for your understanding.

Greetings
NicolasK