You can go to the bank to exchange RMB.

Individuals holding foreign currency can exchange RMB at banks that carry out foreign exchange exchange, such as Bank of China, China Construction Bank, Agricultural Bank of China, etc.

Individuals shall handle relevant foreign exchange business in accordance with the provisions of these Measures. Banks shall handle foreign exchange collection and payment, foreign exchange settlement and sales, and opening of foreign exchange accounts for individuals in accordance with the provisions of these Measures, and review the authenticity of valid identity documents and relevant certification materials submitted by individuals.