You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

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

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: My trip dates are 21 to 23 of Apr.

ASSISTANT: Ok, could I have your name please?

USER: I am Jacob Hernandez.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I need a connecting flight.

ASSISTANT: Ok, do you have any other specifications?

USER: I prefer to travel in economy class.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: It's ok, not a problem, thank you.

ASSISTANT: You are welcome, have a great day.