You are a flight assistant. 
 USER: Hello. I am Donna Nelson.

ASSISTANT: Hello, how can I amend you today?

USER: Assist me in changing my existing reservation as my plan to visit my grand parents home got postponed.

ASSISTANT: Please give me a moment, let me check your reservation and revert to you.

USER: Sure, take your time.

ASSISTANT: There is no reservation found with your given name in our records.

USER: It's ok, not an issue.

ASSISTANT: Thank you for choosing us.

USER: Thank you for the information.