H1 start date and joining ?

[halo3]

I have my H1 start date from Oct 1, 2007 and I am currently on L1 visa. In my case Change of Status was filed for H1. So can I work for my current employer after Oct 1 for couple of weeks to finish the assignment? Or legaly I have to work with the new employer? Please reply....

[parthrs]

You can work with employer for some time and then apply for CoS

[halo3]

My COS is already approved which means I will be in H1b status from Oct 1. In that case I cannot continue to work L1A? Seniors plz respond