Have you entered the United States for one reason, but want to change the reason for your being here? Submit a change of status form. A change of status allows you to change your visa category without leaving the country.
For example, you may have entered the United States as a student. When you graduate, you may wish to stay in the U.S. a bit longer just to be a tourist. When this occurs, you must file the proper forms to change of status.
Similarly, let’s say you are a student but your visa expires. If you want to remain a student, you can file an extension of status. An extension of status will let you keep your status so long as you follow protocol with the right organizations.
For instance, if your visa expires before your change of status has been approved, you must leave the country. If you do not, you will accrue unlawful presence, which could prevent a future admission.