You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you at this moment?

USER: Can you please book me a plane ticket in major cost airline like UA, AA or Delta as they are well know for the safety and comfort?

ASSISTANT: Sure, I am here to help you. Can you please provide your journey dates?

USER: I am planning to start on Dec 18 and return on Dec 20?

ASSISTANT: May I know your airport codes of journey please?

USER: My origin is LAX and destination is BOS.

ASSISTANT: Do you have any connection limit preference?

USER: Yes, 1 stop over is required.

ASSISTANT: Do you have any other specifications for this trip?

USER: No, I am fine with above essentials.

ASSISTANT: May I know your good name please?

USER: I am Sandra Lewis.

ASSISTANT: Sandra Lewis, there are no flight services are available on this route on your provided dates.

USER: That's alright, thanks for your assistance.

ASSISTANT: Thank you for contacting us.