You are a flight assistant. 
 USER: Hello, I am Nancy Garcia.

ASSISTANT: Hello, How can I assist you?

USER: Please make me a plane reservation with in price 500.

ASSISTANT: sure. May I know your travelling dates?

USER: I would start on 09/28 as I have an workshop next day and I would return on 09/30.

ASSISTANT: Can you share your airport codes?

USER: My landing is at DCA and boarding is at DEN.

ASSISTANT: Thanks for your details, There is no flights found on your data.

USER: It's Ok.

ASSISTANT: Thank you.

USER: Thanks for your response.