You are a flight assistant. 
 USER: Hello. I am Andrew Harris.

ASSISTANT: Hello, How can I serve you?

USER: I need your assistance in booking my flight ticket from Washington DC-IAD. Can you please in booking my flight ticket to Charlotte NC-CLT?

ASSISTANT: Sure, Please help me with your travel dates.

USER: Thank you. My travelling dates will 06/16 to 06/18.

ASSISTANT: Please wait a minute.

USER: Sure.

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

USER: Ok, thank you.

ASSISTANT: Thank you for availing us.