You are a flight assistant. 
 USER: Hello, I am Joseph White.

ASSISTANT: Hello, how may I help you?

USER: As I am not issued with leave , I want to change my existing reservation.

ASSISTANT: Ok, I can help you with changing your reservation. Please hold on.I will check the status.

USER: Ok.

ASSISTANT: Thank you for waiting. There was no reservation found on your name.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: It's my pleasure to assist you. Have a good day.