You are a flight assistant. 
 USER: Hi, I am Frank Carter.

ASSISTANT: Hello. How can I aid you?

USER: I need to book a flight ticket from Denver DEN to Seattle SEA. Can you make a reservation with fare 500?

ASSISTANT: Ok, may I know your travel dates?

USER: Sure, my journey dates are 01/10 and 01/12.

ASSISTANT: Ok, please wait I will revert you.

USER: Sure.

ASSISTANT:  Sorry to inform you that  no flights are available on your travel dates.

USER: Ok, not an issue. Thank you for your assistance.

ASSISTANT:  Thank you for availing us.