How to change action when modifier is active

[jpringle1]

i've combed through all the docs and many github issues trying to figure out how to do this very simple thing, and i'm sure it's staring me right in the face, but i just can't figure out how to change the action execute when pressing a key while a modifier is active.

For example: When i hold down alt and press space, i want to send escape instead.

[jtroo]

The fork or switch action sounds like the right one.