You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am John Lee. I am planning to attend  a Tennis Competition in DEN from CLT. Can you find a flight ticket for me?

ASSISTANT: Sure, I am here to help you. Can you please tell me your preferable dates of your journey?

USER: Sure, I am planning to travel on these days that is on 11/15 and back on 11/17.

ASSISTANT: Ok, please give me a minute.

USER: Sure.

ASSISTANT: Sorry for the trouble, there are no flights available on the dates you have given.

USER: Ok, no problem. Thank you for your valuable information.

ASSISTANT: Most welcome. Thank you for reaching us.