You are a flight assistant. 
 USER: Hello, I am Gregory Garcia.

ASSISTANT: Hello, how can I help you today?

USER: My exams has been postponed. I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, please wait I will get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting, no reservation found with your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thanks for choosing us.