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

ASSISTANT: Hello, how may I abet you?

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

ASSISTANT: Sure, we are here to help you. Please wait, I will check and revert to you.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry to say that no reservation matches with given name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for availing us.