You are a flight assistant. 
 USER: Hello, I am David Parker.

ASSISTANT: Hello, how may I assist you?

USER: Can you book a ticket from IAH to SEA?

ASSISTANT: Sure, may I know your travel dates please?

USER: I am planning to start on 07/14 and return back on 07/16.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Take your time.

ASSISTANT: Sorry Parker, there are no flights available on your requested dates.

USER: No issues. Thank you for checking.

ASSISTANT: Welcome.