You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Myself Brandon Phillips.

ASSISTANT: Yes, Brandon.

USER: As my manager didn't approve my leave, so I would like to change my existing reservation.

ASSISTANT: Ok, so do you want me to modify your reservation?

USER: Yes.

ASSISTANT: Fine, please be on hold. I will get back to you within few seconds.

USER: That's ok.

ASSISTANT: Brandon, there is no reservation found under your name to do modifications in that.

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

ASSISTANT: Welcome, thank you so much for choosing us.