You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Donna Young here.

ASSISTANT: Young, how can I assist you today?

USER: I want to book a reservation from Denver to San Francisco in the month of September. My location codes are from 09/10 to 09/12.

ASSISTANT: Sure, can you provide me your airport codes?

USER: My location codes will be from DEN to SFO.

ASSISTANT: Please wait, let me check for the available flights to SFO.

USER: My trip dates will be from 09/10 to 09/12.

ASSISTANT: Sorry, there are no flights available to SFO on 09/10.

USER: That's ok, no problem.I will find some other way to travel.

ASSISTANT: Thank you for contacting us, have a nice day.

USER: Thanks for checking. You are welcome.