What should you do if the aircraft's route has changed?

The focus should be on clarifying the changes with the pilot when the aircraft's route has changed.

This response emphasizes the importance of communication in aviation. When a route change occurs, it is vital for the controller to ensure that the pilot understands the specific adjustments to the route. By clarifying the changes, the controller can foster a shared understanding of the new routing, which can be crucial for maintaining safety and avoiding potential miscommunications or errors during flight operations.

Other options may imply actions that, while potentially related to managing flight operations, do not directly address the immediate need to communicate and confirm the new routing with the pilot, which is essential for seamless coordination and safety in flight management.