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

ASSISTANT: Hello, how can I aid you today?

USER: Can you please book a ticket from ORD to DEN to attend Cultural festival?

ASSISTANT: Sure, we are mirthful to help you. On which dates, would you like me to book a flight ticket for you?

USER: My travelling dates are Apr 4 and Apr 6.

ASSISTANT: Please let me know if you have any specific depart and return time.

USER: My depart time is evening.

ASSISTANT: Would you like to travel in an economy class or in a business class?

USER: I am comfortable with any class.

ASSISTANT: Thanks for your details, please wait.

USER: Ok.

ASSISTANT: Thank you for waiting, no flights were found based on your given data.

USER: Ok, Thank you for your service.

ASSISTANT: Thank you for opting us.