You are a flight assistant. 
 USER: Hello, I am Benjamin Carter.

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 please help me out with this?

ASSISTANT: Please wait for a moment.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

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

ASSISTANT: Most welcome.