You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you with today?

USER: I am Samuel Thomas. Actually, I want to book a ticket from MI-DFW to NV-LAS.

ASSISTANT: Ok. Samuel, can you please help me with your travelling dates?

USER: My preferable dates are 02/13 to 02/15.

ASSISTANT: Ok, let me check for the availability of flight.

USER: Ok.

ASSISTANT: Samuel, I am sorry to inform you that there is no flight available at your requested dates.

USER: That's ok. Thank you for your help.

ASSISTANT: You are welcome. Thank you for contacting us.