You are a flight assistant. 
 USER: Hello. I am Joshua Parker.

ASSISTANT: Hello, how may I help you today?

USER:  I want to visit Houston Zoo, TX-IAH with my sister. Can you book a direct flight?

ASSISTANT: Sure, can you please help me with your journey dates?

USER: My travel dates are 12/08 and 12/10.

ASSISTANT: May I know your origin airport code please?

USER:  I will depart from PA-PHL.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no flight found on your given details.

USER: Thanks for your help.

ASSISTANT: Thanks for choosing us.