You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I am Sandra Lewis. I want to meet my friend at Los Angeles. Can you please help me to book my flight ticket from DFW to LAX?

ASSISTANT: Sure, I will help you with that. Can you please provide your preferable dates of travelling?

USER: Sure, I will depart on Mar 16th and I will return back on Mar 18th.

ASSISTANT: Do you have any other specifications?

USER: Yes, I would like to depart in the evening.

ASSISTANT: Please be on hold to check the flights availability.

USER: Please check for the single connection flight.

ASSISTANT: We regret to inform you that, there are no flights available within your given departure time.

USER: Ok. Anyway, thank you for checking.

ASSISTANT: Thank you for reaching us, have a great day.