It may be possible to extend your non-immigrant visa, assuming you apply for an extension before it expires (see the date indicated on your arrival and departure Form I-94) and your passport is still valid. You must file Form I-539 (Application to Extend or Change Non-immigrant Status), along with a $300 fee, or have your employer file Form I-129 (Petition for a Non-immigrant Worker). If your request is denied, you cannot appeal to a higher office. Your case will be reconsidered only if new facts come to light. If you miss the deadline, you will have to prove the delay was beyond your control and reasonable and that there are no deportation orders against you. Extension is not available if you are in the US on the Visa Waiver Program or a D, C, K or S class visa.