A foreign national must have been lawfully admitted into the U.S. The new employer must have filed a 'non-frivolous' petition while the foreign national was in a period of stay authorized by the Attorney General. A non-frivolous petition is one that has some basis in law or fact. Subsequent to such lawful admission, the foreign national must not have been employed without authorization.
Current regulations, 8 C.F.R. 274A.12(b)(20), authorize employment with the existing employer after a request for extension of H-1B status is filed. The foreign national in this case is employment authorized but the I-9 Form, Employment Eligibility Verification, contains no provision for this authorization. Employers should follow the documentation procedures they currently use for an extension of this sort. Typically, this could involve attaching a copy of the receipt notice for the filed petition along with a copy of the foreign national's I-94 to the I-9 kept on file.