You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How exactly I can serve you the best today?

USER: I want to travel from HOU to OAK, can you help me in doing that?

ASSISTANT: Sure, please share me your trip dates.

USER: My trip dates are Dec 15 to 17.

ASSISTANT: For booking, we need your good name. Please mention it.

USER: I am Susan Clark.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I need a direct flight.

ASSISTANT:  Would you let us know if you have any other preferences?

USER: I prefer normal-cost airline.

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

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Thank you for opting us.