The spouse and unmarried, minor children of the principal alien are entitled to the derivative status, but they are unable to accept employment in the United States. Aliens entering under this classification are considered non-immigrants. The requirements for Canadians and Mexicans wishing to enter under this classification are not the same. After the petition has been approved, the alien must apply for a non-immigrant visa at a U.S. Embassy or Consulate in Mexico.
Canadian citizens have two options.
First , they may have their employer file an I-129 form at the closest regional INS office. This option does not require leaving the U.S. Second, Canadians may return to Canada to re-apply at the port of entry with the same documentation that is required for an original application. Mexican citizens must have their employers renew their labor certification and file another I-129 with their regional INS office in order to extend their stay.