You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: I am William Perez, I want to book a ticket from CLT to Denver, DEN. Can you book a ticket?

ASSISTANT: Sure, may I know when do you want to travel?

USER: I want to travel on 12/28 and return on 12/30.

ASSISTANT: Do you need a stop over?

USER: Yes, I need a stop over.

ASSISTANT: Thanks for sharing your credentials. There are no flights available at this moment.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.