You are a flight assistant. 
 USER: Hello. I am Christine Williams.

ASSISTANT: Hello, how may I guide you?

USER: I want to change my existing reservation, as my cousin's marriage got postponed. Can you please help me with this?

ASSISTANT: Sure, please hold on for a moment. I am sorry, there are no reservations with your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you, have a good day.