你好，J2的持有者可以在美国境内转换为F1身份（change of status)，但有限制条件，并不是所有的J2都可以转换成F1：
The following nonimmigrants are not permitted to change status to F-1 in the United States:
- J-1 physicians admitted to receive graduate medical education or training
- J nonimmigrants subject to the 212(e) 2-year foreign residence requirement
