You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I need a booking from Atlanta to Oakland to attend my sister's baby shower ceremony, can you help me?

ASSISTANT: Sure, may I know your dates of journey?

USER: I will takeoff on 09/11 and my landing will be on 09/13.

ASSISTANT: Can you provide your airport codes?

USER: My arrival airport code is ATL and departure airport code is OAK.

ASSISTANT: May I know your name please?

USER: Myself Dennis Anderson.

ASSISTANT: Sorry, there is no flight found basis on your details.

USER: Oh! that's sad, anyways thank you for assisting me.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.