Need action to change Reaper input

[Tyrannocaster]

I have been trying to get a macro together to accomplish one of the most common multiple tasks I encounter in Reaper and I have hit a wall because it seems that there is no way to change the track input from the default audio to midi other than manually. Can this be right? Using the SWS action that changes the midi channel will only work once you have set the input to midi, and so far I have not been able to figure out how to do that with an action.

I'm hoping there's something obvious I have overlooked.

Anybody?