You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brian Martinez.

ASSISTANT: How can I help you?

USER: Can you book a flight ticket from DFW to PHX?

ASSISTANT: Sure, may I know on what dates would you like to travel?

USER: I want to take off on Dec, 31 afternoon and return on Jan, 2 evening.

ASSISTANT: Do you prefer any halt in between journey?

USER: Yes, I need a halt.

ASSISTANT: Do you have any airline preferences?

USER: No.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there are no flights found on your preferable travel dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.