You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: I am Richard Martin. Can you book a flight ticket from DEN to LGA?

ASSISTANT: Sure, can you please share me with your dates of journey?

USER: Apr, 26 and Apr, 28 are my travel dates.

ASSISTANT: May I know your class preference please?

USER: I am comfortable with any class.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: I found a flight with the connecting flight of fare 100 of Spirit airline, are you ok with this booking?

USER: Please book the flight where return time should be at evening.

ASSISTANT: Sorry, there is no flight found as per your return time.

USER: It's ok, thank you for checking.

ASSISTANT: You are welcome.