Hongkong trademark can't be transferred to China, because the affiliated institutions are different. Trademarks that can be registered in Hong Kong may not be registered in the Mainland! You can only provide the name of the Hong Kong trademark to see if it is registered in the Mainland. If there is no similarity, submitting the application as soon as possible can effectively reduce the risk. If someone applies, they can only give up and change the trademark name, because Hong Kong trademarks cannot be used in the Mainland, and they must hold legal trademarks applied by the Mainland to sell branded products.