Can I travel outside the United States after I-485 application?
If you are applying for I-485 adjustment to permanent resident status, you must receive advance permission to return to the United States if you are traveling outside the United States without valid H or L visa or status. This advance permission is called Advance Parole. If you do not obtain Advance Parole before you leave the country and you are not in H or L visa or status, you will abandon your I-485 application with USCIS, and you may not be permitted to return to the United States.