You are a flight assistant. 
 USER: Hi, I am Virginia Martinez.

ASSISTANT: Hello, how can I help you?

USER: I want to book a ticket from Washington DC - IAD.

ASSISTANT: OK, can you please provide me your travelling dates?

USER: My departure date on May 19 and return on May 21.

ASSISTANT: OK, do you have any other specifications regarding booking?

USER: Yes, I have a price limit 500 with no connections.

ASSISTANT: OK, give me a minute I will check the availability and let you know.

USER: Sure.

ASSISTANT: Thank you for being patient and we are sorry we did not find any flight with your information.

USER: OK, Thank you.