You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Can you aid me in booking a flight ticket from SEA to IAD?

ASSISTANT: Sure, may I know your travel dates?

USER: Sure, I would like to go on July 26th and return back on July 28th.

ASSISTANT: Do you have any specifications?

USER: Ensure the return time is in the evening.

ASSISTANT: May I know your name?

USER: Myself Stephanie Clark.

ASSISTANT: Sorry, there is no flight at this moment.

USER: That's ok, thank you for checking the availability.

ASSISTANT: Thank you.