You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What kind of service you are expecting from us?

USER: I am George Young.

ASSISTANT: Ok.

USER: Please book me a ticket from LAS to DFW to meet my family?

ASSISTANT: Sure, I need your travelling dates that you wish to start and return?

USER: I would like to start on 05/18 and return on 05/20.

ASSISTANT: Sorry George, there are no flights found for your journey, in your travel dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for approaching us.