My friend and his two teenage children are traveling from Paris Gare de Lyon to Verona Porta Nuova, Italy on 22 June 2023. They purchased the Trenitalia 3-Day Pass, and need seat reservations for this journey.
This site is the only one I've found that has seat reservations for sale, but it's asking for the their Interrail Pass number. They don't have one because they have Trenitalia Pass.
What do they do? Dose the Trenitalia Pass number work on this site?