我父母在成都辖区，持绿卡，不太喜欢美国生活，回国已经快2年。
现在想来看我们，据网上消息，必须先主动退回美国绿卡，同时申请B2。但是退回美国绿卡只有在广州领事馆有相关消息，是否必须在广州办理？
-No. They can abandon their green card in any US consulate in China. Here is some information from US Cosulate in Shanghai, and you may find the same information in US Consulate in 成都:
http://shanghai.usembassy-china.org.cn/green_cards_holders.html
Anyway, the procedure should be the same no matter whether you do it in any US Consulate in China.
另外广州领馆明确说明必须先退回美国绿卡才能再申请B2，是否必须办理两次？
-No. They can do these two things at the same time.
