What action should a pilot take when informed by ATC that they may have entered restricted airspace?

When a pilot is informed by Air Traffic Control (ATC) that they may have entered restricted airspace, the appropriate action is to acknowledge the communication. This acknowledgment is crucial as it confirms to ATC that the pilot has received the information and is aware of the situation. Responding with "Roger" effectively communicates this awareness and allows ATC to maintain oversight of the pilot's actions.

While it is important for the pilot to consider their next steps, such as assessing the situation and determining if immediate action is required, the primary initial response to ATC is to acknowledge their instruction. This ensures clear communication during a potentially critical moment.

Promptly acting on the information, such as changing course or reporting the incident, might also be necessary, but it should follow the acknowledgment of the ATC's warning. Therefore, the response of acknowledging with "Roger" is the first vital step in an effective communication process when dealing with airspace concerns.