This MIDI transmit Channel be changed either on the Keyboard itself in the SETUP/GLOBAL menu, or using The Laboratory MIDI Control Center utility that is installed when installing Analog Laboratory software (update 1.2 is now available in the Downloads section).
You can change le Global MIDI Channels for Upper and Lower.
If SplitMod is Off, the keyboard only transmits notes on the Upper Channel.
If SplitMod is On, the keyboard transmits notes on both channels, according to the SplitPnt (split point) setting.
You can change this parameter "on-the -fly" (press SETUP, press 6/GLOBAL, turn the Category/Pararm knob to show UpperCh parameter, turn the Preset/Value knob to change the MIDI channel, press down the Preset/Value knob to enter/confirm, press SETUP to exit), or you can store different settings of the Keyboard Memories and recall them as needed.