You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I support you?

USER: Can you avail me to book a flight from BOS to DEN?

ASSISTANT: When are you planning to travel?

USER: My planned journey dates are Jan 10 and 12.

ASSISTANT: Which type of class do you prefer for your journey?

USER: I am comfortable with any class.

ASSISTANT: Is there any connection limit for you?

USER: Yes, I need a break in my journey.

ASSISTANT: May I know your name?

USER: Robert Taylor here.

ASSISTANT: May I know if you prefer to have any other comforts in your journey?

USER: I want to depart in the evening time.

ASSISTANT:  OK, please wait a moment.

USER: Sure.

ASSISTANT: Sorry Robert Taylor, based on your specified requirements we haven't found any flights in airline database.

USER: Ok, thank you.

ASSISTANT: Thanks for contacting us.