Certain exchange visitors to the United States who are admitted in J-1 status are subject to a 2-year foreign residence requirement.  This means the visa holder must return to his/her home country for at least 2 years at the conclusion of the exchange program.  In the event that a J-1 visa holder cannot return home for that time, a waiver must be obtained from the Department of Homeland Security prior to changing to another status in the US.