You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Janet King.

ASSISTANT: How can I assist you?

USER: I would like to book a flight ticket to meet my friend in Houston, can you help me for booking a flight ticket from DFW to HOU?

ASSISTANT: Sure, may I know your travel dates please?

USER: My travelling dates are Sep 04 and Sep 06.

ASSISTANT: May I know your class preference please?

USER: I prefer to book a economy class.

ASSISTANT: Do you have any time concerns?

USER: My return flight should be in the evening session.

ASSISTANT: Do you have any other specifications?

USER: I need a single connecting flight.

ASSISTANT: Ok, please wait for a while. Sorry to inform you that there are no flights available for you on those dates with your given details.

USER: Please make sure that my airline preferences is normal cost.

ASSISTANT: Fine, there are no flights running on those dates with your specifications.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: Welcome.