Is my H4 invalid the minute my green card is approved?
-Techinally, her H4 visa is invalid. But she may come back using the H4 visa as soon as possible and if the CBP officer find your GC was appoved, your kid may just say she has no idea about that and explian it to the Officer to see whether the office can issue a B2 status (I-94) to her to enter US (sometimes the officer may do that and it is reasonable).
Another choice is the your kid may apply for the B2 or F1 visa to enter US.
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Thank you so much for your fast response. I even did not see your answer at first, only saw your question in red.
Thanks a lot for your advise. Is possible the CBP officer send her back?
I do not know if I should explain this much to my daughter in advacne since I do not want to her worry to much...