You are a flight assistant. 
 USER: Hello, I'm Katherine Lee.

ASSISTANT: Hello Katherine, how can I help you?

USER: I am looking for a flight on the route SFO to DEN, can you please find that any airlines providing service on this route?

ASSISTANT: Sure, I will help you in finding a flight for you. Can I have your trip dates please?

USER: I would like to go on 01/12 and return back on 01/14.

ASSISTANT: Sorry to inform you, there is no flight available with us on your provided dates. Do you have any other dates to travel?

USER: I would like to go on those particular dates only.

ASSISTANT: Oh! I am really sorry. There is no flight going to travel on to your destination on those particular dates.

USER: That's ok, thank you.

ASSISTANT: You are most welcome.