I am a student on F-1 visa since 07. I have done my Masters and used up my OPT. I have an job offer and my employer is ready to sponsor my H1B visa.

My situation is a bit convoluted as:
1> I was in a PhD program [for 1 year] which I am quitting.
2> My F-1 status shall change soon because of that[this week or next]. My grace period will extend till September 2nd week.
3> I have used up my opt and my ead card has expired [filed after my MS].

In this situation how can I transfer onto the H1B smoothly? What documents do I need to submit to the company lawyers? Will I have to leave the country and re-enter? Is so how long will it take. My employer will be filing for premium processing.

Is there any other thing that you would suggest/ I have forgotten.