You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Kevin Davis.

ASSISTANT: How can I help you?

USER: Ia m planning to attend convocation meeting at Las Vegas, can you please help me with booking a flight ticket?

ASSISTANT: Sure, on which dates you like to travel?

USER: Sure, I would like to take off on 07/20 and return back on 07/22.

ASSISTANT: May I know your airport codes please?

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

ASSISTANT: I am sorry no flights found on details.

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

ASSISTANT: Thank you for choosing us.

USER: You are welcome.