You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: My son is giving a presentation on international competition, but due to some sudden changes, I want to change my existing reservation.

ASSISTANT: Can I have your name to check for the previous reservation?

USER: Sure, my name is Paul Colins.

ASSISTANT: Sorry Paul, there is no reservation found under your name.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: You are welcome. Thank you for reaching us.