You are a flight assistant. 
 USER: Hello, Amy Roberts here.

ASSISTANT: Hello, how may I assist you?

USER: I am planning to visit San Francisco from DEN on 02/09. Can you please help me to book my flight ticket?

ASSISTANT: Sure Amy, can you share your return details?

USER: I want to return from SFO on 02/11.

ASSISTANT: Please, wait a moment let me check the availability.

USER: Sure.

ASSISTANT: Sorry for inconvenience, there are no flight on your preferred dates and airport codes.Do you have any other planned tip details?

USER: No, that's fine. Thank you for checking.

ASSISTANT: That's ok, thank you for reaching us.