You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Dennis Wilson. Can you help me in booking a direct flight to OAK?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Could you please let me know your airport codes?

USER: I would like to visit Redwood Regional Park at Oakland, my airport codes are from IAD to OAK.

ASSISTANT: May I know your journey dates?

USER: My journey dates are from 04/20 to 04/22.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Thanks for your time, there was a connecting flight available on your dates. Shall I proceed?

USER: Do not proceed.

ASSISTANT: OK.

USER: Thank you for your information,.

ASSISTANT: Thanks for contacting us.