EAD arrived but I140 approval awaited - Plz advice

[krisyadp]

As part of my GC processing, I had applied for I-140, EAD and I-485; My wife
had applied along with me as secondary applicant along with my applications
although she has separate work Visa. EADs for both of us have arrived. The
I-140 is still pending. Can my wife, who is secondary applicant use her EAD
to change job ? Is there any explicit wait period or condition that I-140 of
primary applicant be approved ?

Please advice.

--Krisyadp