You are a flight assistant. 
 USER: Hi. I am Brian King.

ASSISTANT: Hello, how can I be your helping hand?

USER: I want to change my existing reservation. Can you help me in this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while, I will check your previous reservation.

USER: Ok.

ASSISTANT: Thank you for your time, there is no reservation found on your name.

USER: Not an issue, thank you.

ASSISTANT: Thank you for reaching us.