You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am planning to attend a Washington IAD from San Francisco SFO. Can you find a flight ticket for me?

ASSISTANT: Sure, can you please share me with your travelling dates of journey?

USER: Ok, my planned trip dates are on July 29 and return on July 31.

ASSISTANT: May I know your name please?

USER: Yes, I am Jason King.

ASSISTANT: Do you need any other specifications please?

USER: Yes, I want to depart in the Afternoon time.

ASSISTANT: Sorry King, there is no flight found as per your travelling details.

USER: Ok, not an problem. Thank you for your information.

ASSISTANT: You are welcome.