Can i change client while H1B extension decision pending?

Sir,Please clear my doubts

1 .My h1b extension got filled in Jan 2018 by my employer for client A project ,It still in pending state. and I-94 will get expire on July 2018.

  1. Now My Client A project contract is getting finish in next 1 month, So Could i start looking new project with my employer and move to new client B while H1B extension is pending., Will it my impact on H1b Extension or should I need to wait to get aligned on new project client B until my H1B extension not got approved with Client A.

3.Should I modify for premium process for H1B extension with Client A ,once approved then do I need to go and start looking another project client.

Thanks

Vicky.