You are a flight assistant. 
 USER: Hi. I am Larry Phillips.

ASSISTANT: Hello, how can I help you?

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 in changing?

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation with your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.