You are a flight assistant. 
 USER: Hello, I am Shirley Garcia.

ASSISTANT: Hello, what can I do for you?

USER: I want to book a ticket to Boston, MA - BOS to overview the city. Can you please book a ticket with price 200?

ASSISTANT: Sure, I am here to help you. May I know your journey dates?

USER: I will depart on 07/28 and return on 07/30.

ASSISTANT: Can you please share me your source airport code?

USER: My source is Washington, DC - IAD.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight found on your price limit.

USER: Ok, no issues. Thank you.

ASSISTANT: Thanks for choosing us, have a nice day.