H1B - H4 - H1B Transfer

Hi,

I was working with Employer A on H1-B and resigned in Sept 2020. My attorney filed for H4 COS in Aug 2020 along with EAD. My H4 COS approved and Employer B applied for my H1 transfer in PP. Now my i-94 expired last month in March 2021. Do i have to leave US and go for consulate stamping since my i-94 is expired or I can start working for Employer B when my H1-b transfer is approved.