You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am George Lopez.

ASSISTANT: How best can I serve you now?

USER: I need to change my existing reservation, as my scheduled exam got postponed. Please help me in changing?

ASSISTANT: Sure, I will help you in that. Please hold on, let me check your reservation status.

USER: Ok.

ASSISTANT: Thanks for your time. Sorry George, there is no active reservation on your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for choosing us.