You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Patricia Wilson. We friend's planned a trip to Seattle. Can you please help me in booking a flight ticket?

ASSISTANT: Sure, please provide me your travelling place codes?

USER: The origin airport code is DEN and the destination airport code is SEA.

ASSISTANT: May I know your travelling dates please?

USER: The dates are 05/25 and 05/27.

ASSISTANT: I am sorry Mr.Patricia Wilson, there is no flights on your request.

USER: It's ok.

ASSISTANT: Thank you.

USER: Thank you for your help.