美国签证如何移签？
1. 什么叫移签？ 在哪里办，需要提供什么材料呢？ “移签”(Change of Status)是指申请人在进入美国之后改变其移民身份的过程。由于移民局只受理移民申请的递交，而申请人往往已经在美工作或学习了一段时间，为了节省办理手续的时间和费用，申请人可以通过在境外的“移签”方式实现入境后身份的转换；或者当申请人被拒绝入境而持有的是非移民签证时，也可以借助这种方法获得入境的机会。 “移签”通常是在入境口岸进行的，申请人可以在入境时将移民签证和I-20表一起递交给海关及边境保护部的工作人员，请求他们将其身份由B1/B2变更为F1或M1等移民类别。
当然，这种方式并不是百分之百可行的，因为边境官员没有义务去核查移民签证的身份类别。所以，为了确保能成功移签，建议申请人首先咨询自己户籍所在地的使领馆，看使馆是否提供此服务以及需要什么条件才能提供；如果不行的话，再咨询纽约、芝加哥、洛杉矶、旧金山等城市的总领事馆，看是否有办法通过委托他人代办的方式实现移签的目的(一般总领事馆是不接受个人申请的)。一般来说，纽约、芝加哥、洛杉矶等地的总领事馆都能为申请人提供这种“移签”的服务。
目前，北京、上海、广州等地居民申请F-1学生签证的成功率普遍较高（约98%），且大多可以不用面试即可获签。但是，其他一些类别的签证，尤其是申请非移民签证的游客们就相对比较难了。例如，根据最新的消息显示，从2007年起，北京地区的非移民签证申请者必须亲自前往上海进行面谈了。因此，那些不能获得面签机会的申请者可以考虑使用“移签”的方法来获得入境的机会，然后再想办法将移民身份变更为F1或M1等可接受的类别。
一般而言，“移签”的程序如下所示：
Step One： Get Your I-20 Form Prepared by the School You Are Going to Be Studying at (if applicable); Step Two： Take a Flight Ticket for the U.S. on Direct Flight; Step Three： Arrive in the Airport and Ask the Customs Official there to Convert your Visa Status from B1 or B2 into F1， M1， etc depending upon what you will be studying after reaching America. If he / she does not have any such permission， they would probably ask you to leave USA directly. However， if they agree then it may take another two weeks before you get the final approval about visa status change. After that time period you can start your new life at school or university. Please note this is just an example procedure which could vary according to different airports as well as immigration officials handling the same. Generally one should try these procedures while crossing American ports but in case things do not work out then better approach US Embassy where you are residing currently with proper explanation. In some cases you might even need a letter written by the University explaining their willingness to accept you as student under given circumstances， like when applying for H4 visas. Once again please consult with us only via email since we always prefer to keep our personal contact details private due to various reasons， including safety concerns. We also want everyone here knows more than anything else because we believe knowledge is power and those who seek it shall find it eventually no matter how difficult its journey seems initially！ 最后要提醒一下，虽然