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 in booking?

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

USER: Angela Baker here.

ASSISTANT: Please wait for a moment, while I check for the reservation on your name.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

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

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