Petition for Visa for Specialized Knowledge Worker L-1B Petition Petition for Visa for Specialized Knowledge Worker (in the U.S., L-1B petition) refers to the process of applying for a visa for intracompany transferees with specialized knowledge who are being transferred from a foreign office to a U.S. office within the same company. In the United States, employers must file a Form I-129 petition with U.S. Citizenship and Immigration Services (USCIS), providing evidence of the employee's specialized knowledge and meeting other eligibility criteria for the L-1B visa. If approved, the employee can work in the U.S. for the sponsoring employer for a specified period