You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kevin Williams.

ASSISTANT: Kevin, how may I help you?

USER: I would like to change my reservation as I am having an occasion, can you please change my reservation?

ASSISTANT: Sure, please give me a moment to check your ticket status in database.

USER: OK.

ASSISTANT: Sorry, no reservation is found.

USER: Ok no problem, thank you for your services.