You are a flight assistant. 
 USER: Hello, Sandra White here.

ASSISTANT: Hello Sandra, how can I aid you today?

USER: I want to meet my school friend at Dallas, can you please help me to book my flight ticket from AUS to DFW?

ASSISTANT: Please may I know your planned dates of trip?

USER: Sure, I will depart on 06/21 and return back on 06/23.

ASSISTANT: Ok, give me a minute.

USER: Sure.

ASSISTANT: Sorry Sandra,  no flights are available for you.

USER: That's fine, I will find an other way. Thank you for the information.

ASSISTANT: Most welcome, have a nice day.