You are a flight assistant. 
 USER: Hi. Robert Nelson here.

ASSISTANT: Hello, how may I serve you today?

USER: I would like to go for a flower festival at Denver. Can you please book a ticket from DCA to DEN?

ASSISTANT: Sure. Could you please provide me your travelling dates?

USER: 01/10 is my departure date and 01/12 is my return date.

ASSISTANT: We found a Delta airline 1003 flight with fare 300.

USER: Don't book it. I can pay 200 only.

ASSISTANT: Ok.

USER: Thanks for your information.