You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Carol Baker here.

ASSISTANT: How may I guide you today?

USER: Can you change my flight ticket reservation?

ASSISTANT: Sure, I will help you with that. Please wait for a minute.

USER: Sure.

ASSISTANT: I am sorry to say that there is no reservation found under your name.

USER: Ok, not a problem. May be it is already cancelled.

ASSISTANT: Thank you for reaching us.

USER: Thank you.