You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Karen Thomas here.

ASSISTANT: How may I assist you now?

USER: Can you book a flight ticket for my travel dates that is from 18 Mar to 20 Mar?

ASSISTANT: Karen Thomas, may I know your desired airport codes?

USER: The airport codes are from LGA to MSP.

ASSISTANT: Do you need a connecting flight?

USER: I nee a single connecting flight.

ASSISTANT: May I know your depart and return time?

USER: The return time is evening.

ASSISTANT: Sorry to say, there are no flights available for your journey.

USER: Not a problem.

ASSISTANT: Thank you for connecting with our services.

USER: Thank you.

ASSISTANT: Have a nice day.