You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I would like to celebrate my birthday at Philadelphia with my friends, please book a ticket from DFW to PHL.

ASSISTANT: Sure, we are pleased to serve you.

USER: Thank you.

ASSISTANT: Can you share me your trip dates?

USER: My planned travel dates are Apr 25 and Apr 27.

ASSISTANT: May I know your good name please?

USER: My name is Christine Thompson.

ASSISTANT: Is there any class preference for you?

USER: Any class is comfortable for me.

ASSISTANT: Do you prefer any whistle stop in your journey?

USER: No, I need a direct flight.

ASSISTANT: May I know your depart time and arrival time?

USER: I am fine with any time.

ASSISTANT: Do you have any other requirements?

USER: No more requirements.

ASSISTANT: Sorry to inform you that, currently no flights are running to that location due to some technical issues.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us, we will try to serve you for the next time.