My apologies - I stand corrected. RealCanadian is correct. Here is a FAQ from Murthy chat:
Question : Can a tourist change visa status to F-1? Also, once on F-1, does one have to re-apply to BCIS to be able to change majors while attending the same university? Thanks.
Answer : Since April 12, 2002, a B-2 tourist who files a change of status (COS) with the BCIS to switch to F-1 to study at school, can no longer start attending classes while awaiting the BCIS decision on the COS application. The exception is if the student informed the POE inspector of the intention to study, and that fact is also notated on the B-2 visa stamped in the passport. Each time a student changes majors, etc. the student also is required to obtain approval from the BCIS. Now all the information should be in SEVIS or the Student and Exchange Visitor Information System and easily accessible to the BCIS and the school through the online database.
Date : 2003-06-16