Nonimmigrant - An alien who seeks temporary entry to the United States for a specific purpose, and for a specific duration. The alien must have a permanent residence abroad (for most classes of admission) that he does not relinquish. The nonimmigrant classifications include: foreign government officials, visitors for business and for pleasure, aliens in transit through the United States, treaty traders and investors, students, international representatives, temporary workers and trainees, representatives of foreign information media, exchange visitors, fiance(e)s of U.S. citizens, intracompany transferees, NATO officials, religious workers, and some others. Most nonimmigrants can be accompanied or joined by spouses and unmarried minor (or dependent) children.
In general, you may apply to change your nonimmigrant status if you were lawfully admitted into the United States with a nonimmigrant visa, your nonimmigrant status remains valid, and you have not committed any crimes that would make you ineligible. Most non-immigrants may not accept employment in the United States unless specifically permitted by the service.