You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello, how may I assist you?

USER: I am Edward Thompson and I want to book a flight ticket on 09/13.

ASSISTANT: Ok, may I know your airport abbreviates?

USER: My airport codes are TX-AUS and DC-DCA.

ASSISTANT: Kindly, provide me your arrival day?

USER: I would like to return on 09/15.

ASSISTANT: Please be on hold.

USER: Ok.

ASSISTANT: Sorry, no flights were available on your preferences.

USER: No issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your service.