You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Charles Anderson here.

ASSISTANT: How can I help you?

USER: Please reserve a flight ticket from SFO to DEN for my business conference.

ASSISTANT: Sure, I will  help you to book a flight ticket. Can you please share me your travelling dates?

USER: Thank you for accepting my request, my departure is on Nov 19 and please book my return ticket also on Nov 21.

ASSISTANT: Ok, do you have any connection limit?

USER: Yes, I will prefer single connection for my journey.

ASSISTANT: Ok, may I know your arrival and departure time?

USER: I would like to return in evening time.

ASSISTANT: Sorry, no flights are available on your route.

USER: Oh! Sad to hear that. Anyway, I will go with another airlines. Thank you for the information.

ASSISTANT: Welcome, have a nice day.

USER: Welcome.