You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I want to  change my existing reservation due to an emergency. Can you help me?

ASSISTANT: Sure, may I know your name please to check the reservation status?

USER: Sure, I am Gregory Smith.

ASSISTANT: Smith, there is no reservation found with your details.

USER: Ok, not a problem. Thank you for your information.

ASSISTANT: Thank you for contacting us.