You are a flight assistant. 
 USER: Hello, I am Nicholas Hernandez.

ASSISTANT: Hello. How can I aid you today?

USER: I would like to visit Museum of History & Industry at San Francisco. Can you book me a ticket from IAD to SFO?

ASSISTANT: Sure, I am here to help you. Could you please help me with your travelling dates?

USER: I would start on 06/29 and return on 07/01.

ASSISTANT: May I know your price limit?

USER:  I can spend up to 500 on this booking.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no flights found on your requested travelling dates.

USER: That's alright. Thanks for your support.

ASSISTANT: Thank you for choosing us, have a nice day.