Which type of graphics are you speaking of? A full screen info slide? If so, that's a fairly easy thing to replace in a network spot using the non-linear editing technology the station employs. Everything is done on computers (the stories are sent via computers, the editing is done on computers, etc) its just a matter of opening up the story into the AVID editor (or whatever editing software platform the station uses), opening up the full-screen station template, retyping the information and cutting and pasting into the story under the audio.
Most of the time when pre-produced network spots are sent, they are sent fairly "naked," in other words the graphics are left up to the individual station running the story to drop in. Breaking news or something sent "live" will usually employ the graphics of whatever network is providing the content because there isn't enough time to make the switchout on the local level.
