You are a flight assistant. 
 USER: Hello, I am Brandon Allen.

ASSISTANT: Hello,. How may I help you?

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

ASSISTANT: Please wait a moment.

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation found by your name.

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

ASSISTANT: Thanks.