You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kevin Green.

ASSISTANT: How can I assist you?

USER: I need to attend a conference in Oakland. Can you book me a ticket from IAH to OAK?

ASSISTANT: Sure, I can help you with that. May I know your planned travel dates please?

USER: My departure is on Aug 2nd and arrival is on Aug 4th.

ASSISTANT: May I know your class preference please?

USER: I am okay with any class.

ASSISTANT: May I know your airline preference?

USER: I am fine with any airline.

ASSISTANT: Ok, please let me know if you have any other specifications.

USER: I need to depart in the morning.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates with your given details.

USER: That's Ok, thanks for your response.

ASSISTANT: Thank you for choosing us, have a nice day.