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

ASSISTANT: Hello, how can I aid you?

USER: I want to change an existing reservation, could you help me in changing the reservation?

ASSISTANT: Sure, I am here to help you.

USER: Ok.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for approaching us, have a nice day.