You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Myself Debra Thompson. I need to schedule my trip to travel Denver to attend my sister's marriage. Can you please help me in reserving the ticket from DFW to DEN?

ASSISTANT: Sure, when would you like to depart and return?

USER: I am willing to travel on Dec 20, and again I will return back on Dec 22.

ASSISTANT: Do you have any requirements?

USER: My class preference is business.

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

USER: Not a big deal, I will choose an other way to reach my destination.

ASSISTANT: Thank you for opting us.

USER: Thank you very much for your information.