You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Mary Garcia, want to travel from DCA to AUS. Please help me in booking my ticket.

ASSISTANT: Sure, on which dates you are planning to travel?

USER: I am planning to travel on 05/10 and want to return on 05/12.

ASSISTANT: Sorry, there is no flights available on these dates.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.