This would be a command that would "undo" your last command(s). This would only be viable for mechanical aspects of the game. For instance.
Practicing skills/songs/sups/spells, training, edge/focus/spec/dedication/etc selection.

For example. In a moment of idiocy, I choose the wrong dedication nas a paladin. I type undo dedicatio twohanded or whatever and it undoes the selection. Now I'm saved from having to re-roll and re-empower a paladin because there is no fix for that certain situation as it stands now. Likely for all the other selections also.

This would have to be a timer, or only let your last command, or only if it was never used before etc. Granted this might be very complex, and time vs benefit is likely low. So, odds are its going to get circular filed but I figured it was worth mention.