綠卡如果提交了回美證的131申請卻遲遲等不到打指紋通知，可以隻拿著receipt離境嗎？
-What does "回美證" mean, reentry permit (for green card holder) or advance parole (for I-485 applicant)?
If it is reentry permit, you can leave US duirng the case pending, but if it is advance parole, you cannot leave US until is is approved.
其實幾個月前申請綠卡時才打了指紋，有沒有可能提交一個免打指紋的申請。我在網上看到可以免打指紋，但是不知道如何操作？謝謝8老師
-You cannot do anything. Probably USCIS may just use the fingerprint in thier system for the reentry permit application. If yes, USCIS let you know. If no, USCIS will send you the appointment for biometrics and thus, you need to return to US for it.
