You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Yes, can you tell me your name?

USER: Kathleen Roberts.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: That's ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.