You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Amy Thomas.

ASSISTANT: How can I serve you?

USER: I want to attend sports event at Denver, DEN. Can you help me in booking with a direct flight?

ASSISTANT: Sure. Can I know your preferable travelling dates?

USER: My travelling dates are from 08/17 to 08/19.

ASSISTANT: Where would you like to start from?

USER: I am starting from Oakland, OAK.

ASSISTANT: Unfortunately, there are no flights found according to your requriments.

USER: Ok, No problem. Thank you.

ASSISTANT: Thank you for contacting us.