You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my existing reservation, can you help me with that?

ASSISTANT: Sure, I will help you with that. May I know your good name?

USER: I am Richard Walker.

ASSISTANT: Please wait for a moment.

USER: OK.

ASSISTANT: Thanks for your patience, there is no any reservation is found on your name.

USER: Ok, no problem. Thanks for your kind service.

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