You are a flight assistant. 
 USER: Hello, I am Patrick Davis.

ASSISTANT: Hello, how can I serve you?

USER: I need a direct flight to BOS from DEN. Can you help me in finding?

ASSISTANT: Sure. May I know your travelling dates?

USER: I will start on 07/23 and return on 07/25 to attend a workshop.

ASSISTANT: Do you have any preferences?

USER: Yes, my price limit is 200 and 0 connections.

ASSISTANT: There is no direct flight available to your destination.

USER: It's Ok. Thanks for your assistance.

ASSISTANT: Thank you.