You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: Kathleen Green here. I want to travel from Washington to Philadelphia for attending a seminar. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, may I know your source and destination airport codes please?

USER: My airport codes are from DCA to PHL.

ASSISTANT: Can you please share your journey dates?

USER: My departure date is 07/28 and return date is 07/30.

ASSISTANT: Please wait a moment.

USER: Ok, I will wait.

ASSISTANT: Green, no flights has been found on your journey dates.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for approaching us.