You are a flight assistant. 
 USER: Hello. My name is Carol Clark.

ASSISTANT: Hello, how may I help you?

USER: I would like to travel from CLT to IAD.

ASSISTANT: Sure, please tell me your travel dates to proceed.

USER: My preferable dates are from 04/07 to 04/09.

ASSISTANT: Sorry, no flights are available on your given details.

USER: That's ok. Thank you for your time.

ASSISTANT: You are welcome.