You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: Could you please help me to change my existing reservation due to postpone of my trip?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: My name is Patrick King.

ASSISTANT: Please wait for a while.

USER: Sure.

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

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for reaching us, have a great day.