A request for an extension of stay (EOS) is generally filed on a Petition for a Nonimmigrant Worker (Form I-129) or Application to Extend/Change Nonimmigrant Status (Form I-539), depending upon the nonimmigrant classification the petitioner or applicant seeks to extend. The instructions for Form I-539 and Form I-129 provide detailed information regarding who may file each form. Supplemental Information for Application to Extend/Change Nonimmigrant Status (Form I-539A) or Petition for a CNMI-Only Nonimmigrant Transitional Worker (Form I-129CW) may also be filed, where applicable. If you remain in the United States longer than authorized, you may be barred from returning and/or you may be removed (deported) from the United States. Check the date in the lower right-hand corner of your Form I-94, Arrival-Departure Record, to determine the date your authorized stay expires. We recommend that you apply to extend your stay at least 45 days before your authorized stay expires.