You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Please help me to change my reservation.

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

USER: My name is Carol Parker.

ASSISTANT: Ok, please be on hold.

USER: Sure.

ASSISTANT: Sorry to inform you that, we could not find any reservation against your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for choosing us.