You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: I am Michael Lopez want to visit HOU, can you book a ticket from DFW?

ASSISTANT: Sure, may I know your travelling dates?

USER: Sure, my travelling dates will be 08/25 and 08/27.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no flight is available for you as per your requests.

USER: That's ok, thank you.

ASSISTANT: You are welcome.