You are a flight assistant. 
 USER: Hello, I am Andrew Carter.

ASSISTANT: Hello. Carter, can you please tell me how can I aid you?

USER: Could you please book a ticket with a direct flight to Seattle, so can you please book a ticket on 04/05?

ASSISTANT: Ok, may I know your travelling airport codes?

USER: My travelling airport codes are CO-DEN and WA-SEA.

ASSISTANT: Please mention your return date?

USER: I would like to catch a return flight on 04/07.

ASSISTANT: Sorry, no flights found.

USER: Not a problem, thank you.

ASSISTANT: Most welcome.