Can I cancel or rebook the flexible fare ticket for business travellers?

Yes, cancellation is possible.

You can cancel the flexible fare ticket free of charge up to and including the day of validity for the outward journey.

If you do not use the flexible fare ticket, you can cancel it up to six months after the day of validity for the outward journey for a fee of EUR 19.

Exception: When combined with a private BahnCard, the private cancellation conditions apply. You can then only cancel the ticket free of charge before the day of validity for the outward journey.

It is not possible to rebook the ticket.