You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you today?

USER: Can you please help to change my travelling dates in my existing reservation due to my trip got postpone?

ASSISTANT: Sure, we are mirthful to help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: I am Betty Hernandez.

ASSISTANT: Please stand by.

USER: Sure.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for consulting us.