You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: Andrew Walker here. I want to travel from Denver to San Francisco for attending a seminar. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, can you share your travel dates please?

USER: My travelling dates are from 06/10 to 06/12.

ASSISTANT: Ok, now please share your airport codes?

USER: My airport codes are from DEN to SFO. Make sure my connections limit is 0.

ASSISTANT: Sorry presently there is no direct flight.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you.