From an article in Fast Company:
Philosopher and consultant Peter Koestenbaum spends his days exploring truly big questions that have never sounded more relevant. Here, he reflects on what the shock of death teaches us about leadership — and how to move forward without forgetting.

For another way to view it, check out Harrison Owen’s concept of griefwork, which is the process that we as humans go through every time we encounter change. There’s a brief description here, and more in his book Expanding our now.