You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Owning business trip in San Francisco, can you book a flight ticket for me?

ASSISTANT: Can u provide your travel dates?

USER: Actually, my business trip first is in US, so that has been changed to San Francisco. Could you change an existing reservation to  new one.

ASSISTANT: May I know your name?

USER: Myself Kenneth Mitchell.

ASSISTANT: Kenneth, please provide your airport codes?

USER: My location codes are SFO and MCO.

ASSISTANT: Sorry, there is no reservation by your name.

USER: Ok, thank you for service.

ASSISTANT: Thank you for contacting us.