H1 B Transfer before stamping from Company A to Company B

Hi Saurabh,

I have my H1B Petition approved through employer A on Jan-2012 and my petition is valid until April 1, 2014. But I couldnt go for stamping since I am in UK from 2012(till now). I have the copy of my petition approval notice (I797).My questions are below.

  1. Can i go for stamping through another employer with this same petition.
    If so can the new employer apply any time during the year to apply for a new H1B petition under Cap exempt category?

  2. If i can go for stamping, by when should i go for stamping. Will it be before 1 April,2014?

  3. If by worst case i miss out to go for visa stamping now, any time in future (after April 2014) can a new employer or the same employer apply for a H1B Cap exempt and apply for stamping.

  4. What is the maximum latest date that i can go for stamping with this valid petition(My petition is valid until April 2014)

Kindly request you to help on my questions

Regards