Had Valid H1B - renewal due, will travel to US in H4B, can I look for Job in US and transfer H4B to H1B


I had valid H1-B which is due for renewal now, in past I had traveled to US for 3 months only.

Now I am in India and will be traveling to US in H4B. My questions:

  1. While in US in H4B, Can I look for Job in US and start working and get my H1B renewal and convert my H4B status to H1B status?

  2. Will my past employer cancel my H1B? In that case can I still search for job in US?

thanks and regards,