You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, may I know your name?

USER: I am Ruth Lee.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found under your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.