Samir - thanks for your reply, i sent u a PM
leeya - what ur lawyer recommended "was" the preferred option before BCIS Aug 13th memo. However, after the Aug 13th memo, it is best to inform BCIS proactively. It says that if your sponsoring employer requests cancelation of ur 140, BCIS would not issue RFE but a NOID (notice of intent to deny) and u would have only 30 days to respond. Furthermore, the memo states at a few places that the BCIS expects applicant to inform them of a change. Search the immigrationportal for posts related to Aug 13th BCIS memo for details (especially in AC-21 forum)
goodluck!
-ab