You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you?

USER: I am Justin Perez. Due to my health problem I want to change my reservation as my meeting was got postponed, can you please help me that?

ASSISTANT: Sure, I am here to help you. Please, wait a while.

USER: Ok.

ASSISTANT: Thank you for waiting. I could not find any reservation on your name.

USER: Thank you.

ASSISTANT: Thank you for availing us.