• A passport valid for at least (6) months from the date of issue of visa. The passport (or accompanying previous passport) must contain a previous visa bearing the same classification as that which is now being sought. A visa may be revalidated if it has a remaining validity of not more than sixty (60) days, or has not been expired for more than one year. Each applicant will receive an individual visa, and each Machine Readable Visa (MRV) covers a full page. Therefore, passports must contain a blank, unmarked visa page for each U.S. visa to be placed in the passport.

• The Form I-94 issued by the U.S. Immigration and Naturalization Service (INS) when s/he last entered the United States. The original I-94 should remain firmly stapled in your passport at all times. If the Form I-94 has expired, you should submit a valid Form I-797 Notice of Approval from the INS for each visa applicant.

• A valid Employment Petition (Form I-797) issued by the INS must be submitted. The form will indicate the applicant's current employer and the approved extension of temporary stay.

• A comprehensive letter from the principal alien's employer identifying the applicant and describing in detail the nature and function of the position, the kind of business and what it does, and justifying the need for the visa. The letter submitted must be on the letterhead of the current employer, with an original signature from the company representative and must be addressed to the Visa Office, Department of State.
  
  Sample Employer Letter for revalidation

• A typed original Form OF-156 (Non-Immigrant Visa Application Form) with one passport-size photograph, with white or light background, for each applicant, regardless of age. The photographs must be attached to the respective forms in the designated place. Please spell out the month of birth (i.e., write "January 2," NOT 1/2 or 2/1) Incomplete or improperly filled out applications are returned without visas.
  
  Download Fillable(Type in) OF-156 form in English.
  You can also request forms by sending a fax to Depart of State at 202-663-1608. Sample Fax Letter.

• If the spouse and/or dependent children are applying for visas separately from the principal alien, certified copies of the principal alien's visa and valid I-94 (front and back) must be submitted in addition to all other requirements.

• $45 non-refundable visa processing fee is required for each applicant.(Except the citizens of Canada and Mexico.) Payment may be made by bank draft, cashier's check, money order, or corporate check or checks issued by your attorney's law firm made payable to the "U.S. Department of State." Cash or personal checks are not acceptable. In addition, certain nationalities must also pay a "reciprocity fee." The amount of these fees vary from country to country. In the case of multiple applicants, payment of all application fees may be consolidated in one check, and all reciprocity fees in another. But application fee and reciprocity fees can not combined, because visa application fee and reciprocity fee go into two separate accounts.
  
  The application fee is non refundable regardless of whether the visa is issued or not. The reciprocity fee, if any, would be returned if the visa can not be issued.
  
  Separate fees are required for each individual, even if there are multiple persons are included in a single passport (like children in mother's passport.)
  
  Reciprocity fee for India:
  $25 for visa up to six months, $50 for visa up to one year, $100 for visa more than 1 year. So all H1/H4/L1/L2 etc applicants would normally pay $100 as their visa is for normally 3 years.
  
  Reciprocity fee for China:
  For H-1, H-4: $10 one entry, $20 two entries valid up to three months only.
  For L-1, L-2: $120 for multiple entries up to 24 months; $10 one entry; $20 two entries.

• Cover letter by the primary applicant addressed to department of state requesting the re-issuance of visa.
  Sample Cover letter

US Department of State does not have direct contact with the public. All transactions take place via U.S. mail or commercial courier. While they do not recommend any particular service, FEDERAL EXPRESS picks up daily directly from their offices. The office's mail room is in a different building; items sent via U.S. Postal Service take at least two extra days each way. Include a prepaid air bill for the carrier of your choice to return the documents to you. If you opt for the U.S. Postal Service, you must provide a stamped, self addressed envelope for the postal service of your choice. For safety reasons. U.S. Postal Inspectors recommend that passports sent via the U.S. Postal Service should be mailed in padded envelopes. If you make no provisions for the return of your documents, they will return them via ordinary surface mail.

If the DOS requests certain additional information on applications previously submitted at old address in Washington DC, then the address to send the additional information is:

Applications for only one family can be sent in one package. Processing time depends on seasonal demand. It is best to allow between eight to ten weeks from the date of receipt. In all fairness, the state department office adheres to a strict first-come, first-served policy. If there are time constraints surrounding your application, please do not submit it. Instead, they advise you to apply for the visa at an overseas U.S. diplomatic or consular office.

If you need additional information, please state department can be reached at (202) 663-1213. Timings are Monday to Friday (except holidays) between 2.00pm-4.00 pm(Eastern Time). A recording provides general information at all other times.
You may also reach them by fax at (202) 663-1608.