You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: William Thompson here. Do you have any connection flight from EWR to DEN?

ASSISTANT: Ok, let me know your preferable dates to get a flight for you.

USER: My travel dates are 06/10 and 06/12.

ASSISTANT: Wait for a moment.

USER: Price limit must be 500.

ASSISTANT: I am really sorry, there is no flight for you with your preferences.

USER: That's fine, thanks for your information and great service.

ASSISTANT: Welcome William Thompson.