You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Mark Martin. I am looking for a flight from DEN to DFW, can you help me out please?

ASSISTANT: Can I know your travel dates please to book?

USER: My trip dates are from 07/07 till 07/09.

ASSISTANT: There are no flight available.

USER: That's ok, no problem. Thank you for your help.

ASSISTANT: Thank you for chosoing our agency.