Kindly remember that I do not get a salary here. Your positive rating is the only way I am rewarded for doing my job. So please do not forget to give me 3 or more stars, or any smiling faces, before leaving the site today. Thank you!
ANSWER: Employer B can file for you now, but because your H1B status expired in July 2016, you have to wait for the approval of the H1B for Employer A, and then you can change to Employer B. In other words, Employer A has to be a bridge to Employer B, to be able to change your employer to B.
If Employer A withdraws the request for an extension, then you would have to leave the US and wait for Employer B's H1B to be approved, and then enter the US with a valid H1B visa to be able to work with Employer B.
I hope I have answered your questions. I aim to give you excellent service, even if the outcome is not what you wanted. So I am happy to answer any related follow-up questions you might have, at no additional charge.
And if you want to talk on the phone for 30 minutes, I can send you an offer for that.
Once you have received an answer, please help me get credit for doing my job, by giving me a positive rating of 3, 4 or 5 stars or any of the smiling faces. You can still ask more questions, even after you’ve given a rating.
A BONUS is also appreciated if you feel I've earned it.
And if you have questions in the future, write FOR JAMES in the question and I will be your personal Expert in this category.