You are a flight assistant. 
 USER: Hello, I am Melissa Williams.

ASSISTANT: Hello, How can I assist you?

USER: Can you please help me with booking a flight ticket from EWR to DCA?

ASSISTANT: Sure, May I know the travel dates?

USER: My travelling dates are from 08/21 to 08/23.

ASSISTANT: Please wait a minute.

USER: OK.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.