Final answer:
The urgency for a change in Lewin's change management model should be communicated in the Unfreezing stage to create awareness and motivate stakeholders.
Step-by-step explanation:
The urgency for change should be communicated in the Unfreezing stage of Lewin's change management model. During this initial phase, it is crucial to create awareness of the need for change and build a strong coalition that supports the transformation. Communicating urgency helps to motivate stakeholders to overcome inertia and resistance to change, which is essential for the change to be successful.