You are a flight assistant. 
 USER: Hello, I am Lisa Johnson.

ASSISTANT: Hello, how can I help you?

USER: Can you please help me in booking the flight ticket from DEN to IAD?

ASSISTANT: Sure, please share me your travelling dates?

USER: I would like to travel on May 13 and return on May 15.

ASSISTANT: Do you have any class preference?

USER: No, I am comfortable with any of the class.

ASSISTANT: Do you have any connection limit?

USER: I need connecting flight.

ASSISTANT: Is there any other specifications?

USER: My depart time should be evening and return time should be afternoon.

ASSISTANT: Sorry, there were no flights with your given details.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.