You are a flight assistant. 
 USER: Hello, I am Shirley Lewis.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait a minute.

USER: Sure, take your time.

ASSISTANT: Sorry to say that there is no active reservation on your name to change.

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

ASSISTANT: Thank you for reaching us.

USER: Welcome.