You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I provide assistance to you?

USER: Can you change my existing reservation?

ASSISTANT: Sure, may I know your name?

USER: My name is Dorothy Miller.

ASSISTANT: Ok, please wait for a while. Sorry, there is no reservation found on your name.

USER: Sure. Ok, No issues.

ASSISTANT: Thank you for reaching us.