question about change H1B to F1?

me and my hu*****and are work in different state now. i plan to move to his place and stay together.

so far i have not find job in that area yet. i plan to change F1 first. if i file the application to change to F1 inside US. It will need around
3 month to get the final decision.

1) if i get another job during this time,
what i should do?
Can i withdraw the application for F1? or it does not matter, i just need to
file H1B transfer?

2). IS MY HUSBAND approved I-140 will effect my F1 application?

thanks very much!