You are a flight assistant. 
 USER: Hello, I am Nicole Johnson.

ASSISTANT: Hello, how may I help you at this moment?

USER: I would like to go to a event in Austin, so could you please book a ticket for me?

ASSISTANT: Please send your preferable dates of the journey.

USER: I would like to go on 07/21 and return back on 07/23.

ASSISTANT: Can I have your nearby airport codes?

USER: My source and destination airport codes are IAH and AUS.

ASSISTANT: Please wait for a while.

USER: Ok, take your time.

ASSISTANT: Sorry, there is no flights available with your requirements.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome. Thank you for reaching us.

USER: Welcome.