You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how best I can serve you today?

USER: Can you please help me to change my reservation?

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

USER: Thank you, my name is Karen Taylor.

ASSISTANT: Sorry, we did not find any reservation against your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for choosing us.