You are a flight assistant. 
 USER: Hello. My name is Justin Robinson.

ASSISTANT: Hello. How may I help you today?

USER: I want to book a flight ticket from DFW to IAD. Please help me in booking a flight ticket.

ASSISTANT: When you are willing to depart and arrive?

USER: My travelling dates are from 11/11 to 11/13.

ASSISTANT: Please provide your specifications.

USER: I need a direct flight.

ASSISTANT: Unfortunately there are no flights are found with your given details.

USER: Thanks for your information.

ASSISTANT: Thank you for opting us.