You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation due to sudden change in my family trip dates. Can you help me out?

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

USER: Thank you.

ASSISTANT: Wait a moment please.

USER: Susan Smith here.

ASSISTANT: Susan Smith, we haven't found any reservation under your name in our database.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.