You can request an advance parole while your Form I-485 adjustment of status is pending. But in interest of caution, overseas trip while a status application is pending is discouraged for an applicant with previous immigration violations which may potentially render such applicant inadmissible. You may travel if you are certain that you have not violated an immigration law that may render you inadmissible when you return to complete your adjustment application processing. Not all violations of immigration law are obvious and so, it may be wise for you to either remain in the US until your case is concluded or consult with an experienced attorney before your overseas trip.
Answered on Aug 28th, 2013 at 3:53 PM