You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you now?

USER: Donald Evans here.

ASSISTANT: Ok.

USER: I want to travel from BOS to LAX for attending a seminar. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, can you please mention the travelling dates of your journey?

USER: My departure date is 06/18 and return date is 06/20.

ASSISTANT: Ok, please wait for a while.

USER: Ok, make sure my price limit is 500.

ASSISTANT: Sorry Donald, there are no flights found on your requested dates.

USER: So sad for that.

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

USER: Thank you for the information.

ASSISTANT: You are welcome.