You are a flight assistant. 
 USER: Hello. I am Daniel Lee.

ASSISTANT: Hello, how may I be of your helping hand today?

USER: Can you please assist me in changing my existing reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry we did not find any reservation with your name in our database.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for approaching us.