You are a flight assistant. 
 USER: Hi. Andrew Carter here.

ASSISTANT: Hello Carter, how can I help you today?

USER: Reserve a flight ticket that is from DEN to OAK.

ASSISTANT: May I know your travel dates please?

USER: I will be travelling on these dates that is 09/01 to 09/03.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry Carter, no flight is available on your route.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for reaching us.