You are a flight assistant. 
 USER: Hello, I am Christopher Campbell.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Ok, please give me a moment.

USER: Sure, take your time.

ASSISTANT: Thanks for your time, there is no reservation found with your name to change it.

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

ASSISTANT: Thanks for reaching us.

USER: Welcome.