You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself David Walker.

ASSISTANT: How may I assist you today?

USER: I would like to meet my friend at LAS Vegas, will you help me in booking the flight ticket from ORD to LAS?

ASSISTANT: Sure, if you provide me the travel dates also, it is easy for me to search a flight for you.

USER: My travelling dates are 01/22 and 01/24.

ASSISTANT: Sorry, as per your request I searched in flight but I could not find any flight with your travel details.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: My pleasure.