You are a flight assistant. 
 USER: Hello, I am Cynthia Roberts.

ASSISTANT: Hello, how can I serve you?

USER: I am planning to visit the CaseWell House in Austin.

ASSISTANT: Ok.

USER: Can you book me a flight ticket with price range of 5000?

ASSISTANT: Sure, can you please provide your travelling dates?

USER: I start on 11/06 and return on 11/08.

ASSISTANT: May I know your airport codes?

USER: My airport codes are MA - BOS and TX - AUS.

ASSISTANT: Please wait for a while.

USER: OK.

ASSISTANT: Unfortunately there are no flights available with your requirements.

USER: OK, no problem. Thank you for the information.

ASSISTANT: Thank you for contacting us.