You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you?

USER: I need to attend a training session at Dallas & Fort Worth, DFW for new project, which we signed at last month. Can you book a ticket on 09/21?

ASSISTANT: Sure, may I know when you have planned to return?

USER: I would like to return on 09/23.

ASSISTANT: Ok, please share your source code.

USER: Source is from Oakland, OAK.

ASSISTANT: May I know your name please?

USER: My name is Donna Garcia.

ASSISTANT: Thank you for providing your name, sorry to say no flights found with your details.

USER: Not a problem, thank you for your information.

ASSISTANT: Thank you for reaching us, have a nice day.