You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Larry Davis here. As my manage did not approved my leave, so I want to change my existing reservation. Can you please help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait a moment I will check your reservation status.

USER: Ok, take your time.

ASSISTANT: Sorry to say, I did not find any reservation found under your name.

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

ASSISTANT: Thank you for choosing us, have a nice day.