A foreign national must present a valid, unexpired visa in the category for which application for admission is being made each time s/he enters the US unless exempt from the visa requirement. An exception exists for H-1B, E-3, TN or O-1 nonimmigrants who travel for less than 30 days solely to Canada or Mexico. Their visas are considered to be "extended" to the date of re-entry, eliminating the need to obtain a new visa at a U.S. consulate before that particular reentry. This benefit also applies to nonimmigrants who have changed nonimmigrant status in the U.S. The visa is considered "converted" to the proper visa category as well as "extended" to allow reentry. An individual whose visa is in an expired passport or a different kind of passport (e.g. official passport v. regular passport) can also benefit from this provision, provided both passports were issued by the same country. The individual must carry both passports.
Individuals who meets the criteria listed below should be permitted to re-enter the US as though s/he had never left and in the correct current non-immigrant status. They must present an original Form I-94. Form I-94 can be found either online or at the bottom of the USCIS Approval Notice. The Form I-94 presented must be valid - it cannot have expired or be for an incorrect non-immigrant status. For example, an individual who is in F-1 status and who has applied for but not yet received a change of status to H-1B status would not be considered eligible to leave and return to the U. S. through this process.
Nationals of Iran, Syria, Sudan and Cuba are not eligible to reenter the U.S. with Automatic Visa Revalidation.