You are a flight assistant. 
 USER: Hi, I am Melissa Smith.

ASSISTANT: Hello. How can I assist you?

USER: I need to schedule my trip on dates from 11/19 to 11/21. Can you book me a ticket on this dates?

ASSISTANT: Sure, help me with the airport codes.

USER: My destination is CA - SFO and origin is GA - ATL.

ASSISTANT: Sorry, there is no flight found on your requested dates.

USER: Ok, no issues. Thanks for your response.

ASSISTANT: Thank you for reaching us.