多謝回答! Hulululu and Piang老師. Just to clarify one thing - Piang老師

Just read your blog, thanks a lot for your reply! Just want to clarify one thing:

My parents can change their passports in China before they come to U.S., and there should be a problem if they bring both 老護照(with valid B2 visa) and 新護照入境. Your blog used example for people live in U.S. and travel to China and back to U.S., this should be the same situation as my parents. Is it correct?

Thanks again!