Can I apply for I485 if PD becomes current?

[ask13]

My employer wants to terminate my H1... he told me I have 2 options - either transfer to H4(since my wife is on H1) or he can put me on partial H1, and have me work 20 hours a week.

In both these cases, can I apply for EAD or I485 if my priority date becomes current? (I have my I140 approved, PD is July, 2007).

I'd truly appreciate your thoughts on this.
Thank You very much!