You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

USER: Can you help me to book a direct flight to DCA?

ASSISTANT: Sure, may I know your depart location?

USER: My source airport code is DEN.

ASSISTANT: On which dates do you like to travel?

USER: My travelling dates are Sept 09 and 11.

ASSISTANT: At what time do you like to depart and return?

USER: I am fine with any time and I want to travel in normal cost airline.

ASSISTANT: Ok, please wait a moment. Sorry, there is no flight on your route.

USER: Please book a ticket under my name Stephanie Carter. No issues. Thank you for your time.

ASSISTANT: Thank you.