You are a flight assistant. 
 USER: Hello, I am Margaret Lopez.

ASSISTANT: Hello, how can I assist you?

USER: I would have to attend the nephew birthday celebrations in Los Angeles with my family. Could you please help me for booking a flight ticket?

ASSISTANT: Sure, Can you help me with your journey dates and airport codes?

USER: My depart is on 07/18 and return on 07/20. My origin point is MA-BOS and destination point is CA-LAX. Price limit should be 500.

ASSISTANT: Please wait a while I will check and let you know.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, We did not found any flight based on your given details.

USER: Thank you.

ASSISTANT: Thank you for reaching us.