Once you are acquired, normally the acquirer will have the more say on decisions making. Sometime the acquirer management team is less experience than you but welcome to the real world. The acquirer will always try to be dominant in management decisions although sometimes their decisions will lead you into trouble. Wait for the right time to react and never run down your superior although you know that your experience is better than him. Participate in department meetings and minute it properly. Finally what you advice will go to the grapevine and finally to the top.