I am planning to return to Bern from Milano with large luggage and a bike on 26 August 2023. Unfortunately, I couldn’t reserve a direct train from Milano to Bern on that day for some reason at the ticket office in Italy. (Possibly there might be some constructions on the rail on that day.) Instead, the officer suggested detouring via Zurich HB and I already bought the direct train from Milano to Zurich HB with a bike slot and tickets for me and my bike from Zurich HB and Bern on 26 Aug. So, I would like to book the bike space of the IC 81 train (12:44-13:58) but I couldn’t book it for some reason. How can I solve this issue?