You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Can you help me to book a flight ticket from LAS to PHL?

ASSISTANT: Sure, can you share your travelling dates?

USER: Ok, please book for the dates Apr 14 and 16.

ASSISTANT: Do you have any preferences?

USER: Yes, I need a direct flight.

ASSISTANT: May I know your name?

USER: My name is Betty Martin.

ASSISTANT: Sorry, there is no direct flight on your given dates.

USER: That is ok, thank you for assisting me.

ASSISTANT: Thank you for opting us.