query on movement from L1B to H1B with same employer if L1B is expiring on sep25 2016

[nlnchoudhary]

Hi,

Kindly plz reply to my query and assist

Currently I'm on L1B visa from an employer and its getting expired in the month of sep 25 2016.
In this year 2016 I have applied for the Fresh H1B visa by the same employer and I got selected in the lottery.

I will be moving out of status of my current L1B from sep 26 to oct 1st for 5 days.

Kindly please suggest me on what will be the right time to apply for L1B extension in order to maintain status and also can i work on H1B visa with the same employer from oct 1st even if my L1B extension is under progress

Thanks
nlnc