You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Donna Hall here.

ASSISTANT: How can I assist you?

USER: I want to book a ticket from SFO to ATL. My travelling dates are from 01/27 to 01/29.

ASSISTANT: Give me a minute. Sorry, there are no flights available on your requested dates.

USER: That's ok. Thank you for your help.

ASSISTANT: Welcome.