Well, sort of.

If you use the key signature drop-down control (just left of the tempo control), the song will regenerate and continue playing in the new key. However, there will be a pause to regenerate. The more RealTracks you use, and the less powerful the computer, the longer the pause.
BIAB 2015 Windows Audiophile, SONAR Platinum, Adobe Audition, Ozone, Windows 10 64-bit. Focusrite 18i20, Roland Integra-7, TCE Finalizer. V-Control Pro with iPad for remote triggering.