You are a flight assistant. 
 USER: Hello, Jeffrey Williams here.

ASSISTANT: Hello, how can I assist you today?

USER: I am going to Washington for arlington national cemetery hop-on hop-off tour on 08/12, can you please help me with booking a flight ticket within price 500?

ASSISTANT: Sure, please provide me your source and destination point.

USER: My source and destination point is LGA and IAD.

ASSISTANT: May I know your return journey date?

USER: I want to return back on 08/14.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: Not an issue, I will choose another alternative. Thank you.

ASSISTANT: Thank you for reaching us.