You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you today?

USER: I am Stephen Mitchell. Can you please help me to make my flight reservation from DEN to OAK?

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: Yes, I have to start my journey on Oct 30 and I will return in the morning on Nov 1.

ASSISTANT: Ok, do you have any specifications?

USER: I only prefer for a single connection flight.

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

USER: Sure.

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

USER: Sad to hear that. Anyway, thank you for checking.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.