You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Due to an urgency I want to cancel my existing reservation.

ASSISTANT: Ok, may I know your name please?

USER: My name is David Lopez.

ASSISTANT: Please wait for a moment.I will check the existing reservation on your name.

USER: Sure.

ASSISTANT: Sorry David, there is no reservation found on your name. Thank you for approaching us.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: You are welcome.