The interviewer wants to know that you are aware of the need to always lead by example.
"All the time!" As a leader, your actions, decisions, and demeanour are always under some form of scrutiny. The most stressful workplace situations often surround change so it's a great idea to talk about a time when your organization went through a major change. Change can be very challenging for some people. Discuss how you accept change with a positive attitude.
Perhaps a new software system was being implemented. Maybe your company was being acquired. Perhaps a change occurred in your senior leadership. Talk about how easily your team could have leaned towards negativity by becoming unmotivated, or acting fearful of the change. Highlight that you have genuine excitement surrounding the possibilities that come with change and that this excitement rubs off on your team.