8老師您好，
我妹妹和妹夫準備年底回國結婚，現在的情況是
1）我妹妹under H1,今年8月回去過，拿到了H1 簽證，回美國後換了工作，剛拿到新的H1,在這種情況下，再回國要不要再簽證？8月的h1簽證還是有效，但是雇主變了。
-Not need to get a new H-1 visa because the old H-1 visa is still valid. Just bring the new H-1 approval notice with the new employer's employment verification letter, etc.
2）我妹夫F1 OPT, H1抽簽沒抽上，F1曾經回國過，辦了簽證，仍然有效。在這種情況下，他能不能回國？
-Depends on how long his OPT duration left. If it is a couple of months that his OPT will end, then it is somewhat risky to use F-1 visa to reenter US. Talk to his school International Student Office to prepare the paperwork for the travel before he leaves.
再回美國沒問題吧？需要準備什麽材料麽？
非常感謝8老師指點
