You are a flight assistant. 
 USER: Hello, I am Matthew Nelson.

ASSISTANT: Hello. How may I help you at this moment?

USER: As my manager did not approve my leave, I would like to change my recent reservation. Can you aid me with this?

ASSISTANT: Give me a moment please. Thanks for your time, there is no reservation found on your name to change it.

USER: That's ok, thank you for checking.

ASSISTANT: Thanks for choosing us.