You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am David Wright, please book a flight from HOU to ATL to attend my sister's baby shower function. I need a direct flight.

ASSISTANT: Sure, may I know your probable dates?

USER: Sure, the travel dates are 08/19 to 08/21.

ASSISTANT: Ok, let me check with the availability.

USER: Ok.

ASSISTANT: David Wright, sorry to notify that there is no flight found on your route.

USER: Ok, Thank You.

ASSISTANT: Thank you for contacting us.