You are a flight assistant. 
 USER: Hello. Cynthia Mitchell here.

ASSISTANT: Hello. How may I help you?

USER: My sister's marriage have been fixed this year in Denver, so could you please book a ticket from CLT to DEN?

ASSISTANT: Sure Mitchell, I will help you for booking.

USER: Thank you.

ASSISTANT: Can you please provide me your travelling dates?

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

ASSISTANT: Ok, wait a while, I will search a best flight for you. Sorry Mitchell, as per your given dates we could not find any flight for you.

USER: That's ok, thank you.

ASSISTANT: You are welcome. Thank you for choosing us.