You are a flight assistant. 
 USER: Hello. My name is Samuel Moore.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to my business meeting got postponed. Can you help me with that?

ASSISTANT: Sure, I am mirthful to help you. Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, we are sorry to say that no reservation was found in our database on your name.

USER: Ok, No problem. Thank you.

ASSISTANT: Thank you for your presence. We hope to serve you again.