Advance Parole
Advance Parole is permission for certain foreign nationals, who do not have a valid immigrant visa, to reenter the U.S. after traveling abroad.
Note: If you do not apply for Advance Parole before leaving the U.S., the U.S. Citizenship and Immigration Services (USCIS) considers you to have abandoned your adjustment of status application, and may not permit you to return to the U.S.
Humanitarian Parole
If you are outside the U.S. and must travel to the U.S. temporarily because of an urgent business or personal situation, you can apply for a humanitarian parole document to be paroled into the U.S. on humanitarian grounds, if you cannot obtain the necessary visa and any required waiver of excludability.
Note: You cannot use Humanitarian Parole to circumvent normal visa issuing procedures, and is not a means to bypass delays in visa issuance. Parole is an extraordinary measure sparingly used to bring an otherwise inadmissible alien into the U.S. for a temporary period of time due to a very compelling emergency.
Benefits of Advance Parole
You do not have to obtain a visa from an American Consulate for returning to the U.S. after traveling abroad.