This seams really difficult but all I want to do is take the hands of my character and mirror it on a y axes because I put the thumb on the wrong side of the hand. As far as I can tell there is no way to do it with the edit tools provided in blender.
It looks like all I can do is duplicate the object, crop it down to just that part, translate it to a negative y then join it again. In contrast in light wave all you would do is select the surfaces and hit CTR+V (I think, been a while), place your line and hit enter.
So is there an easy way to do this?