Discover can be swiped at any place where UnionPay cards are accepted, just make it clear to the store clerk. There is no need to call in advance, I will consume it directly when I return home. But because I didn't call in advance, the credit card center found out that I had swiped my card in China and asked me to call to explain via email (to prevent theft), so I still called. If you are still in the United States now, it is best to get one.

Hope to adopt it, thank you!