Moving from H4 to H1

Hello Friends

My situation is that I entered US on H4 in Jan 2013 and got H1b petition approved in Oct 2013.

I started a job for 2 months but due to some emergency I had to fly back India for a while. I have some location constarint due to my family in US which my employer is not willing to cater. So I am planning to come back to US on H4 since my H4 stamp is valid. My Question is

  1. Once I am back on H4 can I use my approved H1b petition through some other employer?

  2. If my previous employer withdraws my petition can I still be able to use approved petition through another employer who can sponsor me(I hope this would be cap exempt)?

Thanks

  1. Once I am back on H4 can I use my approved H1b petition through some other employer?

YES

  1. If my previous employer withdraws my petition can I still be able to use approved petition through another employer who can sponsor me(I hope this would be cap exempt)?

YES