Revoke I 140

I have my I140 approved in May 2019. After that my H4 EAD and H1B extension also got approved. Currently, I see that there is minor typo error in my middle name (One letter missing) in approval notice I797A of I140 and my attorney is telling to fill I 140 amendment. If I140 amendment is filled then Can I change employer while I140 amendment is pending ? Can new employer use original I140 for H1B extension and for H4 EAD ? Do I need to wait for 180 days after I140 Amendment approval for changing job ?