You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I would like to cancel my recent reservation due to postpone of my conference. Could you please help me?

ASSISTANT: May I know your name please?

USER: I am David Smith.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: No worries, thank you for your help.

ASSISTANT: Thank you for reaching us.