You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I'm Joseph Clark. My Scheduled examination dates has been postponed. So, I would like to change my reservation.

ASSISTANT: Sure, please give me a minute.

USER: Sure, take your time.

ASSISTANT: Please share your travel dates.

USER: I would like to take off on 06/14 and return back on 06/16.

ASSISTANT: Can I know your airport codes?

USER: My source airport code is SEA and the destination airport code is DTW.

ASSISTANT: Please give me a minute.

USER: Sure.

ASSISTANT: Sorry, there is no flight available on your request.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: You are welcome.