You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hi,. How may I help you?

USER: I planned  a trip to LGA from DCA from 07/31 to 08/02. I need a flight ticket of 500.

ASSISTANT: OK,give me a minute to check. May I know your name please?

USER: My name is Donald Jackson.

ASSISTANT: Sorry Donald,we did not find any flights matching your requirements.

USER: OK, no matters. Thank you for helping me.

ASSISTANT: Thank you for choosing our service. Have a nice day.