Leaders who choose to shift an organizational culture after having existed in, and contributed possibly unwittingly or intentionally to the current culture for a period of time, are courageous. By making this choice, committing to the outcome, and following through in words and deeds, they expose themselves to the risk that they might not succeed. Few leaders are used to failing. Most prefer to take calculated risks that are stacked in their favour.
The leader who sets out to change a culture they have been party to requires courage because the end result will be either guts or glory. There will be no middle ground; the culture change will not happen without personal, intentional change by a courageous leader.