You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Jack Collins.

ASSISTANT: How can I help you Jack?

USER: Due to a sudden meeting, my trip to Las Vegas has been changed. Could you help me in changing the reservation?

ASSISTANT: Yes, please give me a minute. I'm sorry, there is no reservation found.

USER: That's ok.

ASSISTANT: Would you like to travel on any other dates?

USER: No, thank you for your time.

ASSISTANT: Thank you for reaching us.