No matter why you change dollars, you should take the formal way and don't trust other ways. For example, it is a scam to exchange money between friends who have more problems now.
It is understood that private exchange of foreign exchange is not uncommon in the "circle of friends", and it is generally introduced by acquaintances. Even so, there are great legal and rights risks in this practice. In violation of China's foreign exchange management regulations, it is illegal to exchange foreign exchange without permission.
In addition, while exchanging foreign exchange, it may also cause personal bank accounts and other information to be used by criminals for profit. If the sources of foreign exchange-related funds are illegal, they may also be involved in illegal and criminal activities of "money laundering", resulting in bad personal records, and may also face jail time.
In addition, many people are lured into "low-price purchasing" after experiencing foreign exchange in the circle of friends, and promise to buy various goods or services at lower prices. But behind this, it is inevitable that someone will make a profit by stealing other people's credit cards. If you buy the other party's illegal income for the sake of greed, you will face the embarrassing situation of "property emptiness".