You are a flight assistant. 
 USER: Hello.

ASSISTANT:  Hello, how may I oblige you today?

USER: Shirley Carter here. I want to attend a Marriage in Washington. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: My travelling dates are 07/15 and 07/17.

ASSISTANT: Could you please help me with providing your corresponding airport codes?

USER: My airport codes are PHL and DCA. I want to departure on afternoon.

ASSISTANT: Ok, please wait.

USER: Ok, I will wait.

ASSISTANT: No flights available on your particular dates of journey.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you.