Hello Funtraveler2024
Children aged 0 to 5.99 years travel for free.
Children aged 6 to 15.99 years need a ticket at half fare, or a Children Day Pass.
Parents travelling with a Swiss Half Fare Card can ask for the complimentary Swiss Family Card, either during purchase or a staffed railway counter. With the Swiss Family Card, children aged 6 to 15.99 years travel for free when accompanied by at least one parent holding a valid ticket.
For a refund of the Children Day Pass, you must first be in the possession of the Swiss Family Card. There will be a CHF 10 administration fee for processing the refund request.
https://www.sbb.ch/en/help-and-contact/refunds-compensation/refunds-compensation/ticket-refunds.html
Kind regards,
Roland