Removing concrete plug in rough-in

I have a roughed in flange in my basement but it is filled with a cement plug. I assume that the cement is to protect the vent and should be removed. I plan to put the bathroom in and need to remove the plug. How do I do this? Am I supposed to remove the cement without damaging the flange or am I supposed to chip out the flange and replace it?

Thanks

 

Cement Plug

It's Probobly A Thin Layer Of Cement With Wadded Up Newspaper Or A Big Rag Under It. Just Break It Out....