Sorry for troubling you guys, but I just have to know.. could this be Patricia Tallman in the elevator in ST TNG episode "Half a Life", time index 08:19? That's season 4. Was she already working there then?
This is Cameron Oppenheimer playing Tactical Officer Ensign Kellogg. The actress actually 'stood in' for Gates McFadden on several occasions (as did Patricia Tallman due to their similar physique) which I'm assuming is why you're mistaking the two of them.
As far as I can tell, her only line (despite appearing in over a dozen episodes) was "Counselor?" in TNG: Eye of the Beholder