L1 to H1 transfer grace period of earlier approved h1

[bavina]

Hi,

 

I am currently on L1 visa in US from company A and I have a H1B approved unused petition. 

I got a job offer from company B and ready for processing h1 transfer in premium processing on date 8/11/15. 

I would like to know once it is approved(assuming there is no RFE and approval would take 15 days i.e. 8/25/15). 

Can i join company B sometime in 14th of Sept as i need to serve 15 days notice period with company A. is there any grace period? 

Will there be any complication in future visa or extension or GC?

 

thanks,

[jairichi]

Once a COS is approved you cannot work for L1 employer. Not even for a day.