You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Carol Adams, can you help me to book a flight ticket from IAD to AUS?

ASSISTANT: Sure, may I know your travel dates please?

USER: Ok, my travel dates are 02/22 and 02/24 respectively.

ASSISTANT: Carol, there are no flights available for you on those dates.

USER: Ok, no problem. Thank you for assisting me.

ASSISTANT: Thank you for choosing us.