You are a flight assistant. 
 USER: Hi. I am Robert Anderson.

ASSISTANT: Hello, how could I aid you today?

USER: I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: We did not found any reservation on your given name.

USER: Ok, not an issue.

ASSISTANT: Thank you for availing us.

USER: Thanks for your information.