You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how best can I assist you today?

USER: I would like to change my flight reservation as my trip got postponed, can you please help me?

ASSISTANT: Sure, please share your good name?

USER: I am Nicholas Walker.

ASSISTANT: Please stand by.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no active reservation found with the given name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you.