You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Patrick Lee.

ASSISTANT: How may I help you? Nice to meet you Patrick Lee.

USER: Please help me in changing my reservation, as I need to attend an urgent meeting here on those dates.

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

USER: That's ok, thank you.

ASSISTANT: Thank you.