You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I am planning to travel from AUS to DCA.

ASSISTANT: Sure, could you please share me with your dates of journey?

USER: My travelling dates are 05/28 and 05/30.

ASSISTANT: Ok, may I know your name please?

USER: My name is Sarah Johnson.

ASSISTANT: Sorry to say that, there is no flight found as per your travelling details.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: You are welcome.