A forced change costs nothing
Where the reason is attributable to the carrier, it has to reissue the ticket if a seat is available on the alternate flight, or endorse you to another carrier with that carrier's consent, without charging a change fee.
Article 24, source: Civil Aviation Administration of China — Regulation on the Management of Public Air Transportation Services for Passengers (source dated 2021-04-21; read July 25, 2026)