You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, I am here to help you. May I know your good name please?

USER: John Hernandez here.

ASSISTANT: Please wait for some time.

USER: Ok.

ASSISTANT: Thanks for waiting. Sorry, no reservation found on your name.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.