You can also do manual Remote Overrides to assign Reason parameters to knobs/sliders/buttons on your control keyboard/surface, see “Remote Override”.
If a MIDI Port of your connected control surface/keyboard is already used by the Easy MIDI Inputs function (see “Automatic set-up using the Easy MIDI Inputs function”), this detection will override this and automatically remove the MIDI In Port from the Easy MIDI Inputs list.MIDI inputs not selected here or on the Sync page (see “Advanced MIDI - The External Control Bus inputs”) are available to other programs.For example, if you lock a control surface to the Main Mixer, you will always have control over levels, pans and additional channel strip parameters - see “Remote controlling the Main Mixer” and “Remote controlling multiple mixer channels”. You could also have dedicated controls for transport, Undo/Redo, sequencer track MIDI focus selection, etc.