我听说主动退回美国绿卡能换十年内多次往返的签证,
-Not 100%, but most likely.
有没有人知道具体怎么操作的?是不是跟B2签证一样的流程?
-Give up your GC by providing a completed I-407 and the GC to the US Consulate in China. At the same time apply for the B2 visa as usual.
Check the US Embassy/Consulate website for details. You can refer to this website also: