回複：Thank you for your advice.

As long as I know, unless your I40 is denied (no one wants to see this result), you can keep using EAD card until your 485 is approved. It doesn't matter what kind of job you have and how many jobs you want to switch. All you need to do is to renew the EAD once a year (pay $175, could not remember to USCIS). You only have to go back to China to get your H4 when your I-140 is denied. Best wishes.