You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Can you help me to book a flight from LAS to DEN in this week?

ASSISTANT: Sure, let me know your travel dates please?

USER: My travelling dates are July 14 and 16.

ASSISTANT: Do you have any time concern?

USER: I am fine with any time.

ASSISTANT: Ok, is there any class preference?

USER: No.

ASSISTANT: Can I know your name please?

USER: My name is Donna Lewis.

ASSISTANT: Sorry to inform you that there are no flight services available on your given dates.

USER: No issues, thank you for your time.

ASSISTANT: Thanks for reaching us, have a nice day.