1. Go to the bank: First, users need to go to the branch or business outlet of the bank and choose the window or counter that provides foreign currency exchange services.

2. Prepare valid documents: As a requirement for foreign currency exchange, users need to prepare valid identification documents, such as passports and ID cards.

3. Improve the application form for foreign exchange: the bank will provide an application form for foreign exchange, and users need to fill in relevant information, including the amount of foreign exchange and the amount of cash carried in Hong Kong dollars. According to the limit set by the Bank of China, the maximum amount of cash an individual can bring into the Mainland is HK$ 20,000.

4. Exchange: After submitting the application form, the bank staff will check the documents and materials provided by the users. After confirmation, the user can pay HK$ in cash and confirm the converted RMB amount.

5. Collect RMB cash: After the exchange is completed, the bank staff will hand over the exchanged RMB cash to the user. Please note that some banks may provide electronic payment methods, such as transferring money to China bank cards or providing mobile payment channels such as Alipay and WeChat for recharging.