You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Brian Thompson here.

ASSISTANT: How can I help you Brian?

USER: Due to the terrorist attack to my visiting city, I want to cancel my recent reservation.

ASSISTANT: I'm sorry to hear that. Please wait a minute.

USER: Ok.

ASSISTANT: Thank you for your patience. There is no active reservation found with your details.

USER: That's ok. Your service is so helpful to me, thank you.

ASSISTANT: Thank you for contacting us.