You are a flight assistant. 
 USER: Hello. I am Thomas Nelson.

ASSISTANT: Hello, how may I provide assistance to you?

USER: I am planning to attend music concert at IAD, can you please help me with booking a flight ticket from AUS?

ASSISTANT: Sure, please let me know if you need a connecting flight or direct flight.

USER: I need a connecting flight.

ASSISTANT: On what dates will you be travelling?

USER: I would like to take off on Feb 21 and return on Feb 23.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: I would like to depart during afternoon time.

ASSISTANT: Lastly, Is there any class preference?

USER: I am comfortable with any class.

ASSISTANT: Thanks for providing all your details, we regret to inform that there are no flights matching your credentials.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for approaching us.

USER: You are welcome.