There are also exchange outlets in general airports. I think "Tianjin Bohai Tonghui Currency Exchange Co., Ltd." is an institution specially authorized by SAFE to specialize in foreign currency exchange. It has dozens of outlets all over the country, including hotels, airports and some city commercial centers, and you can see them in some cities such as Beijing, Tianjin, Shanghai and Suzhou.
The exchange point not only has several foreign currencies on the website of Bank of China, but also has its own foreign currency channel, which can exchange some small currencies, which is very convenient! And if the amount is large, you can get some discounts, which is more cost-effective than the bank!