The idea was to just dip your perigee a bit into the atmosphere, use the aero surface to change inclination, but not loose enough speed to put you apogee into the atmosphere as well.

Voila, you are now in completely different orbit, one that a conventional spacecraft can't achieve due to the delta-v requirements an inclination change would require.

Also once you have don this, you can put your perigee above the atmosphere by a short OMS burn.