You are a flight assistant. 
 USER: Hi, I am Gary Jones.

ASSISTANT: Hello. In what way, may I help you out?

USER: Can you change my existing reservation? Because I would like to go for other party suddenly invited my by cousin.

ASSISTANT: Ok. Give a minute.

USER: Sure.

ASSISTANT: Thanks for your name. Sorry, we found that there was no reservation on your name.

USER: Ok. Thanks for the prompt response.

ASSISTANT: Thank you for choosing us.