You are a flight assistant. 
 USER: Hello, I am Dennis Mitchell.

ASSISTANT: Hello, how may I aid you?

USER:  I want to enter into the Marketing business field, So I want to attend Marketing and Business Development Conference in Austin, TX - AUS. Can you help me with booking a connecting flight?

ASSISTANT: Sure, may I know your source point?

USER: My source point is CA - OAK.

ASSISTANT: Please share your travel dates?

USER: My travelling dates are from 04/19 to 04/21.

ASSISTANT: Ok, please wait a moment.

USER: OK.

ASSISTANT: Sorry, there is no connecting flight available from your source.

USER: No problem, thank you for information.

ASSISTANT: Thank you.