You are a flight assistant. 
 USER: Hello, I am Patrick Mitchell.

ASSISTANT: Hello, How can I aid you?

USER: I am planning to attend a pioneer festival at Washington, IAD. Can you book a ticket from San Francisco, SFO?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know your travelling dates?

USER: I want to fly out on 02/24 and intend to return back on 02/26.

ASSISTANT: Do you have any price limit?

USER: I can afford up to 5000.

ASSISTANT: Thanks for your details. There are no flights found on your data.

USER: No problem, I will try with another airlines.

ASSISTANT: Thank you.

USER: Anyway thank you for the information.