I am in J-1 now and have got a waiver. I filed I-140 and I-485 1.5 yrs ago and is still waiting for the response. Since H-1B is temporarily unavailable, I plan to apply for EAD and AP soon. My question is: in this case, do I need to apply for H-4 now together with the EAD and AP in order to keep legal status, or can I change to H-4 later if my I-140 fails? Thanks.