You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How may I be of your assistance?

USER: I am Melissa Wilson. I want to book a flight ticket on 04/06 and return on 04/08, can you help me with booking?

ASSISTANT: Sure, may I know your journey codes?

USER: Yes, my airport codes are CA-LAX and DC-IAD.

ASSISTANT: Please wait for sometime.

USER: Ok.

ASSISTANT: Unfortunately there is no flight found with your reuirements.

USER: That's ok. Thank you for the response.

ASSISTANT: Thnak you.