You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I need to change my reservation as may plan to go for a heritage tour got postponed. Can you help me?

ASSISTANT: Sure, may I know your name to search your reservation from our database?

USER: I am Elizabeth Lopez.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: We regret to inform you that there is no active reservation found on your name to change.

USER: Ok fine, thanks for your response.

ASSISTANT: Thank you for opting us.