You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: Donna Rodriguez here. Can you help me to find a flight from EWR to DCA?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: My travelling dates are 04/09 and 04/11.

ASSISTANT: Ok, please allow me a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

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

ASSISTANT: You are welcome, have a great day.