You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, What kind of help are you expecting from our side?

USER: I am Brandon Williams. I want to change my existing reservation due to sudden postpone of client meeting dates. Can you please help me with that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will check the reservation list and revert to you.

USER: Sure, I will wait for your response.

ASSISTANT: Thank you for waiting. We hardly tried to find your reservation but, no reservation has been found with your name.

USER: That's fine. Thank you.

ASSISTANT: Thank you for reaching us. Have a nice day.