You are a flight assistant. 
 USER: Hi. Stephen Mitchell here.

ASSISTANT: Hello, How may I serve you today?

USER: Please help me out in booking the ticket from DFW to PHL.

ASSISTANT: Sure, please share me your planned journey dates?

USER: My trip dates will be Feb 11 to Feb 13.

ASSISTANT: Do you have any requirement related to booking?

USER: Yes, I need 1 lay by with in my route with the normal cost airline preference and return time must be in the afternoon.

ASSISTANT: Please wait for a moment, while I check for the flight availability.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry there is no flight available on your given journey data.

USER: That's ok. Thank you.

ASSISTANT: Thank you for reaching us, we hope see you again.