Extending your visit when you enter in non-immigrant status, such as business visas, tourist visa, student visas, religious visas, working visas
If you decide to extend your stay in the United States, you apply for the extension with U.S. Citizenship and Immigration Services (USCIS) on the Form I-539, Application to Extend/Change Nonimmigrant Status before your authorized stay expires.
Remaining in the United States past the date authorized, may bar you from returning and/or you may be removed (deported) from the United States.
Check the date placed by the immigration officer, in the lower right-hand corner of your Form I-94, Arrival-Departure Record, to be sure of the date your authorized stay expires.
It is recommended that you apply to extend your stay at least 45 days before your authorized stay expires. However, as long as it is received by USCIS prior to the expiration date, you should be fine.
While you wait for a response you will remain legal under the "120 day tolling period."
Under current Service policy, if a decision is not made with respect to pending Change of Status or Extension Applications within the tolling period (120 days), aliens admitted to the United States until a specific date begin accruing unlawful presence on the 121st day after the expiration of their Form I-94.
Important: Due to the current backlogs, which can extend beyond six months, aliens who remain in the United States while the E/S (extension of stay) or C/S (change of status) is pending may incur a 3-year or even a 10-year bar to admission if the application is ultimately denied.
In order to avoid problems, through no fault of their own, regarding "unlawful presence," the Service has decided that Nonimmigrants who were admitted until a specific date and who apply for E/S or C/S and whose applications have been pending beyond the 120 day tolling period should be considered to be in a period of stay authorized by the Attorney General, so long as certain requirements are met.
The Service has further decided that the period of stay authorized by the Attorney General includes the E/S or C/S applications for the entire period that it is pending.
As a practical matter, this policy applies only to those Nonimmigrants who were admitted until a specific date and also whose I-94 has expired while the E/S or C/S application is pending.
If the Service approves the E/S or C/S application, the nonimmigrant will be granted a new period of stay authorized by the Attorney General, which will be retroactive to the date the previously authorized stay expired. In these cases there is no unlawful presence.
USCIS generally allows you 30 days to depart the U.S. starting from the date on the letter notifying you of their decision to deny an extension. If you do not depart within 30 days, you will be considered deportable.
USCIS cautions that if you are refused permission to extend your stay, you may encounter problems with Consulates overseas the next time you apply for a U.S. visa because their computer records will indicate that you did not leave the U.S. within the time frame of your initial period of entry.
Be sure to keep your rejection letter and proof of the date of your departure (a boarding pass is the best thing, but passport stamps showing entry into another country is also helpful) to give the consulate the next time you apply for a new visa.
Having those may mitigate your apparent overstay and could improve your chances of renewing your visa without the five year restriction usually applied to people that have overstayed their visit.
Staying beyond your authorized period can result in bars to re-entry (3-year or 10-year bars) and may affect future visa applications.
Current processing times can extend beyond six months. Plan accordingly and apply well in advance of your expiration date.
Keep all documentation related to your extension application, including the rejection letter and proof of departure if denied.