You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Michael White here. I need you to book a flight ticket from LGA to DCA.

ASSISTANT: Sure, may I know your trip dates?

USER: November 23 and 25 are my planned travel dates.

ASSISTANT: Could you let me know your class preference?

USER: I am comfortable with any class.

ASSISTANT: Do you have any requirements?

USER: I need to depart in the evening.

ASSISTANT: There are no flights available.

USER: That's ok. Thanks for your time.

ASSISTANT: Thank you for choosing us.