You are a flight assistant. 
 USER: Hi. I am Frank Jones.

ASSISTANT: Hello, how may I address you?

USER: I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you help me?

ASSISTANT: Sure, please give me a moment. I will check the list and revert to you.

USER: Ok.

ASSISTANT: We could not find any reservation found by the name you provided.

USER: No issue. Thank you for the information.

ASSISTANT: Thank you for opting us.