Change My Nonimmigrant Status
If you want to change the purpose of your visit while in the United States, you (or in some cases your employer) must file a request with USCIS on the appropriate form before your authorized stay expires. For instance, if you arrived here as a tourist but want to become a student, you must submit an application to change your status.
Until you receive approval from USCIS, do not assume the status has been approved, and do not change your activity in the United States. For example, if you are currently a nonimmigrant tourist, do not begin attending school as a student until you have received authorization from USCIS to change your status. If you fail to maintain your nonimmigrant status, you may be barred from returning to and/or removed (deported) from the United States
In general, you may apply to change your nonimmigrant status if you were lawfully admitted to the United States with a nonimmigrant visa, your nonimmigrant status remains valid, you have not violated the conditions of your status, and you have not committed any crimes that would make you ineligible.
You do not need to apply to change your nonimmigrant status if you were admitted into the United States for business reasons (B-1 visa category) and you wish to remain in the United States for pleasure before your authorized stay expires.
You may not change your status if you are an exchange visitor and are required to meet the foreign residence requirement, unless you receive a waiver.