You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Mark White. I am planning to visit Houston to meet my friend who works's at space center of Houston. Can you book a ticket from Atlanta, ATL?

ASSISTANT: Ok, may I know your travel dates?

USER: I will depart on 08/28 and return on 08/30.

ASSISTANT:  Provide me your destination point?

USER: Destination point is Houston, IAH.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT:  Sorry no flights are available on your travel dates.

USER: Ok, no problem, thank you.

ASSISTANT:  Thank you for availing us.