请问绿卡送达到地址需要本人签收吗，
-No.
还是像一般的信一样直接放进门口的信箱？
-Yes.
第一次寄送不知道什么原因没有收到，退回移民局了，
-Did you track it?
昨天已经去要求了重寄，现在想让它寄到一个PO box而不是以前填的住址的信箱，
请问绿卡可以寄到PO box吗？
-I think so. But you have to inform USCIS to change your I-485 address. So, if you have never changed your living address after you filed I-485, you may just call USCIS to verify whether your I-485 address is your home address (correct address), instead of changing your mail address to mailbox in case it confuses USCIS.
现在如果想要更改地址的话，需要怎么办，是否只要打移民局的客服电话就可以？
-Call it.
