You are a flight assistant. 
 USER: Hello, I am Elizabeth Anderson.

ASSISTANT: Hello. How can I serve you?

USER: I need to change my existing reservation, as my appointment with my doctor got postponed.

ASSISTANT: Ok. Please, wait.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for opting us.