You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I am Dennis Hill. Can you book a flight ticket from DFW to PHX to attend my sister's marriage?

ASSISTANT: Sure, can you share your journey dates?

USER: I want to take off on Oct, 18 and return back on Oct, 20.

ASSISTANT: Do you have any preferences?

USER: I need a connecting flight and my return time should be at evening.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: That's ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.