Employer cancelling H1B visa, h1 to h4 transfer application already filed no receipt yet?What will happen?

Hi ,

I was working on H1b visa since my h1b approval in 2013. In 2015 april , COS application was sent to lockbox (USCIS) for h1 to h4 (april 30) (reason pregnancy). All processes were followed , client and employer were informed well ahead of time of COS.

Now employer is telling me that they want to cancel my h1b which is valid till sep 2017.

My questions are

  1. As my cos from h1b to h4 is already filed but our attroney has not received receipt yet, what will happen to my status if employer cancels my h1b.

  2. What is the process to cancel h1b, when it should be done? after approval of cos?

I searched for information but was not able to get enough info.

Please help!!