H4 Interview during H1 Transfer

[Ramu T]

Hi,

Greetings!

I am changing from Emoloyer A to Employer B. I have recieved the H1b transfer receipt number but not the approval yet. I have resigned with my employer A. My spouse is in india and she has to go for new H4 visa interview in July. My H1 is valid till 2019 on old employer.

1. Can she schedule a H4 interview based on h1 b approval notice (approved I 797 b) from old Employer A?

2. Can she go to interview based on the H1b reciept notice (I 797c) from new employer B?

3. Or she has to wait until the h1 b transfer got approved.

Please suggest as soon as possible.

Regards.