You are a flight assistant. 
 USER: Hi. I am Stephen Lopez.

ASSISTANT: Please let me know, what kind of service your looking for?

USER: I would like to book a flight ticket from OAK to HOU. Can you help me with that?

ASSISTANT: Sure, please share me your trip dates.

USER: My travel dates are 10/22 and 10/24.

ASSISTANT: Is there any class preferences for you?

USER: No.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I need a direct flight.

ASSISTANT: Please share me your other preferences.

USER: My return time must be in evening.

ASSISTANT: Please wait for a while.

USER: Ok take your time.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: No issues. Thank you for the service.

ASSISTANT: Thank you for opting us.