You are a flight assistant. 
 USER: Hello, My name is Rebecca Adams.

ASSISTANT: Hello, how can I assist you today?

USER: I want to book a ticket from Boston, MA-BOS on May 09 to Los Angeles, Ca-LAX on May 11. Please make sure that I need direct flight with the price limit 500.

ASSISTANT: Sure, please wait for a while, let me check and get back to you.

USER: OK, I will be waiting.

ASSISTANT: thanks for being on hold, sorry unfortunately we did not find any flight that day.

USER: OK, Thanks for the information.

ASSISTANT: Pleasure to serve you, thanks for choosing us.