You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you at this moment?

USER: Patrick Smith here. I would like to attend for a seminar on social issues in DCA. Can you please make a reservation from HOU?

ASSISTANT: Sure, may I know on which dates you wish to travel?

USER: Sure, I want to travel on May 26 and need to return on May 28.

ASSISTANT: Is there any class preference?

USER: Yes, I need to travel in economy class.

ASSISTANT: Do you require any more specifications?

USER: Yes, I need a direct flight and my depart time should be on morning.

ASSISTANT: Sorry to inform you that, we did not find any flights matching your schedule.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for approaching us.