You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: As my interview date has been changed, I want to change my reservation. Could you help me?

ASSISTANT: Sure, can I know your name?

USER: Dorothy Robinson here.

ASSISTANT: Ok. I have found your previous reservation. Can you tell me your new dates of your interview then I will book your ticket?

USER: Sure. I am travelling on 04/16 and 04/18.

ASSISTANT: Ok. What's your interview location?

USER: My airport codes are OAK and ATL.

ASSISTANT: Ok. Sorry Dorothy Robinson, there is no flight with these details.

USER: It's ok. Thank you for assisting me.

ASSISTANT: Most welcome.