You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Myself Alexander Jackson.

ASSISTANT: How may I aid you today?

USER: I want to change my existing reservation, can you help me?

ASSISTANT: Sure, please wait a moment.

USER: Ok, I will wait for your response.

ASSISTANT: Sorry Jackson, there are no active reservation available on your name.

USER: That's ok, may be it went wrong during at the time of booking. Anyway, thank you for the information.

ASSISTANT: Thank you for reaching us.