You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I would like to book a ticket from IAH to LAS, can you please help me out?

ASSISTANT: Sure, I am happy to help you with that. Can I have your travel dates please?

USER: I am travelling on these dates Oct 17th and 19th.

ASSISTANT: Ok, please let me know your good name.

USER: Elizabeth Allen here.

ASSISTANT: Do you have any specifications to  get best flight for you?

USER: I need single connected flight.

ASSISTANT: Do you prefer any specific airlines?

USER: I prefer normal-cost airlines.

ASSISTANT: Sorry to inform you that no flight is available to you on your dates.

USER: Ok no problem, thank you for your services.

ASSISTANT: Thank you for choosing us, have a good day.