You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How may I be at your service?

USER: Please help me in modifying my reservation, As my meeting with my clients has been changed to some other place.

ASSISTANT: Ok.

USER: Can you help me?

ASSISTANT: To modify your reservation, may I have your name please?

USER: Charles Brown, is my name.

ASSISTANT: Please standby, I will check your previous reservation and let you know the status.

USER: Ok, I will wait.

ASSISTANT: Sorry, there was no reservation on your name to change.

USER: Ok, I think it does not reserved here.

ASSISTANT: Thank you for approaching us, have a good day.

USER: Anyway, thanks for your service.