You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Christopher Harris here.

ASSISTANT: How may I assist you today?

USER: Can you please help me in changing my recent reservation? As my planned trip has been postponed to some other dates.

ASSISTANT: Sure, I will help you. Please allow me a minute.

USER: Sure, take your own time.

ASSISTANT: Christopher Harris, I am really sorry to inform you that there is no active booking done on your name.

USER: Oh! That's ok, thank you for giving the information.

ASSISTANT: Thank you for reaching us. Have a great time.