Permission to return to the United States after travel abroad granted by DHS prior to leaving the U.S. The following categories of people may need advance parole: people on a K-1 visa, asylum applicants, parolees, people with Temporary Protected Status (TPS) and some people trying to adjust status, while in the U.S. If these people do not apply for advance parole before they leave the United States, they may be unable to return. Go to the DHS, United States Citizenship and Immigration Services (USCIS) to learn more.
Source: U.S. Department of State.