140 approved. Can I shift to another company?

[kakarla.kishan]

Hi.

My H1 B visa (6 years) is expiring early 2012. I got my 140 approved from my current company. So, I can extend my visa for another 3 years as I understand.

Now I want to shift to another company ASAP. Can I do this and use those 3 years? If yes, when should I do this? Should I first get my visa extended for another 3 years and then transfer my H1?

Or Can I do it right away?