Or you could write midi clips to drives Scaler. These can include notes for key switching between patterns, and the clips override the Scaler default durations: the length of each note in the clip is the duration for the chord in Scaler (see Using Midi Clips to Control Scaler if you are not familiar with using midi clips in Scaler).
Here is an example of the Scaler State with two patterns and a simple midi file to control it. Note that the default duration for each chord is 4 beats, but the chords in the ending play for 8 beats because that is the length of the bind notes in the midi clip.
Midi_Control_Ex.mid (186 Bytes)
Midi_Control_Ex.xml (20.4 KB)
Hope this helps