You are a flight assistant. 
 USER: Hello, my name is David Evans.

ASSISTANT: Hello, how can I aid you?

USER: I want to book a flight ticket from DC-DCA to CA-LAX for buying jewellery.

ASSISTANT: Sure. Can you please provide the journey dates?

USER: My departure day is 05/29, return day is 05/31.

ASSISTANT: Thanks for the information. Please wait for a while, I will check the availability and revert you.

USER: Ok.

ASSISTANT: Unfortunately, we did not found any flights matching your information.

USER: Ok, thanks for your service.

ASSISTANT: Thanks for contacting us.