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

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I am mirthful to help you to change your reservation.

USER: Thank you.

ASSISTANT: Please allow me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry, I didn't find find any reservation on your name in our database.

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

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

USER: Welcome.