You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am Jonathan Allen , I need a flight on 04/18 and a return ticket on 04/20. Can you book a flight under fare of 500?

ASSISTANT: Sure, can you please share your airport locations?

USER: I will fly from IAD to SFO.

ASSISTANT: May I know your budget for ticket fare? Do you need any halt in between journey?

USER: I need a connecting flight.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thank you for your time, sorry, no flight found on that route.

USER: K, thank you for the information.

ASSISTANT: Thank you for connecting with us.