How about not paying the patent maintenance fee?

Legal analysis: If the patentee fails to pay the annual fee on time or the amount paid is insufficient after the year of granting the patent right, the patentee shall pay the annual fee within six months at the latest, and at the same time pay the late fee. If the payment time exceeds the prescribed payment time for less than one month, no late payment fee will be charged. If the payment time exceeds the prescribed payment time for one month, 5% of the full annual fee of the current year will be charged as a late fee.

Legal basis: People's Republic of China (PRC) Patent Law.

Article 43 The patentee shall pay the annual fee from the year when the patent right is granted.

Article 44 In any of the following circumstances, the patent right shall be terminated before the expiration of the time limit: (1) Failing to pay the annual fee as required; (2) The patentee waives his patent right in writing. Where the patent right is terminated before the expiration of the time limit, it shall be registered and announced by the patent administration department of the State Council.