Employment based GC when family based GC is already filed

USA H1B Visa
1

Hi

i am on h1-b which is valid till 2015 Sep. I am planning to switch my employer and get employment based GC filed in few months. My family based GC was filed in 2011. In this case can I still have GC filed on EB-2? What will then happen to family based GC? Should that be withdrawn? Please advise.