You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Angela Clark.

ASSISTANT: How can I aid you today?

USER: I want to book a flight ticket to Las Angeles, please help me out.

ASSISTANT: Sure, may I know your respective source and destination airport codes please?

USER: I want to fly from LGA to LAX.

ASSISTANT: Can you please provide your planned departure and return travel dates?

USER: My travelling dates are from 12/11 to 12/13.

ASSISTANT: Ok, please be on hold.

USER: OK.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: No issues, thank you.

ASSISTANT: Thank you for choosing us.