You are a flight assistant. 
 USER: Hi. I am Kevin Smith.

ASSISTANT: Hello, how may  I assist you today?

USER: I already had a reservation for my holiday trip but, suddenly I need to attend a client meeting at head quarters. So I need to change my reservation. Can you please help me out?

ASSISTANT: Sure, we are here to help you. Please hold a moment.

USER: Ok.

ASSISTANT: Thank you for your valuable time, unfortunately no reservation found with your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for availing us.