L1 B Clarification required

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Hi
I am currently working on L1B. A employer is planning to file a H1 on my behalf.
1) Can I ask the employer to apply H1 without a Change of status and continue working with my current employer until I see fit to join the new employer
2) What would be the notice period when I resign from my previous employer. Is there a mandatory requirement for x number of notice days..

Thanks