You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Susan Baker.

ASSISTANT: How may I aid you?

USER: Can you please help me in changing my existing reservation which I have made previously to Los Angeles?

ASSISTANT: Sure, I will help you with the change of flight reservation. Wait for a moment please.

USER: Sure, I will wait for your response.

ASSISTANT: Thanks for your time Susan. But I am sorry to inform you that there is no flight reservation on your name to change it.

USER: Ok, not an issue. May be something went wrong while booking the ticket previously. Anyways, thank you for your time.

ASSISTANT: Thank you.