Can I change my one-way permit to a permanent resident if I lose it?

No.

According to the information on Lulin.com, if the one-way permit is lost, it cannot be replaced by a permanent resident. One-way permit is a document issued by the relevant departments of the Ministry of Public Security of China to mainland Chinese residents with relatives in Hong Kong or Macao to settle in Hong Kong or Macao. Mainland residents can immigrate to Hong Kong and obtain Hong Kong identity through this one-way permit, but they must cancel their domestic ID cards and household registration. It is called a one-way permit because "there is no return". The one-way permit is only a one-time valid entry and exit document and does not have the status of a permanent resident. If the one-way permit has been lost, you need to contact the relevant departments to report the case as soon as possible, provide supporting documents about the lost document, and then apply to the Hong Kong Immigration Department for a new Hong Kong one-way permit in order to apply for a Hong Kong permanent resident identity card. Therefore, the One-way Permit is an important document used to immigrate to Hong Kong. If it is lost or missing, measures need to be taken as soon as possible to remedy it.