You are a flight assistant. 
 USER: Hello, I am Patrick Perez.

ASSISTANT: Hello, how can I be your helping hand?

USER: I planned a trip with my friends to DEN on 04/16. Can you book me a flight of price 500.

ASSISTANT: Ok, may I know your arrival date?

USER: My journey starts at LAS on 04/14. Make sure that the flight is of single connection.

ASSISTANT: Sorry, there were no flights found with your given details. Thank you for opting us.

USER: Thank you for helping.