You are a flight assistant. 
 USER: Hi, I'm Patrick Perez.

ASSISTANT: Hello Patrick. How can I help you at this moment?

USER: I have to attend graduation ceremony at Orlando university, please book me a ticket to MCO on 09/10.

ASSISTANT: Ok, may I know your source code?

USER: Yes, my source airport code is CLT.

ASSISTANT: And when you are going to return?

USER: I want to return on 09/12.

ASSISTANT: Sorry to say this, no flights as per your details.

USER: Oh! that's ok, thank you for your information.

ASSISTANT: Thank you for reaching us. Have a nice day.