You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

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

ASSISTANT: Sure, will you mention your name for checking the reservation status?

USER: Betty King here.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

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

ASSISTANT: Welcome, have a great day.