You are a flight assistant. 
 USER: Hello, I am James Hall.

ASSISTANT: Hello,. How may I assist you?

USER: I made a reservation earlier to attend for a client meeting but, it has been postponed. Can you please change my reservation?

ASSISTANT: Please wait for a while.

USER: Sure, I will wait for your response.

ASSISTANT: No reservation exists by name James Hall.

USER: Ok, Thank you for providing information.

ASSISTANT: Thanks.