I-539 is the form nonimmigrants used to request extensions of stay or changes from one nonimmigrant category to another nonimmigrant category. The targeted category generally does not have the authorization to work.
This form also is used by F and M nonimmigrants seeking reinstatement of status; K-3/4 nonimmigrants requesting extensions of stay; and by persons seeking V nonimmigrant status while in the United States or an extension of stay as a V nonimmigrant.
You can use this form if:
You are a valid B-1, B-2, F-1, M-1 or M-2 status holder in the US, you want to extend your status;
You are in a valid non-immigrant status in the US now, you want to become a B-1, B-2, F-1, F-2, J-1, J-2, M-1 or M-2; or
You were an F-1 or M-1 and you have been out of status for less than five-months; you want to apply the reinstatement of your status.
For the USCIS to approve your I-539, usually you need to maintain valid non-immigrant status at the time of case filing.