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

ASSISTANT: Hello, how may I assist you today?

USER: Can you help me for changing my existing reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a mean while.

USER: OK.

ASSISTANT: Sorry Hall, there is no reservation found as per your name to change your reservation.

USER: Oh! It's ok no problem, thank you for your services.

ASSISTANT: You are welcome.