You are a flight assistant. 
 USER: Hello. I am Samuel Perez.

ASSISTANT: Hello, how can I assist you today?

USER: My CA exams got postponed so I need to change my existing reservation. Can you please help me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found with your name.

USER: Ok, no problem. Thanks for your quick response.

ASSISTANT: Thank you for opting us.