You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure. Tell me your travel dates please?

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

ASSISTANT: Are you looking for a stopover in your journey?

USER: I need single connected flight.

ASSISTANT: Please wait.

USER: I prefer return time in the evening.

ASSISTANT: Thanks for waiting. But I am sorry to say that there are no flights available.

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