You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Can you please assist me to change my active reservation as my meeting was changed?

ASSISTANT: Sure, on which name your previous ticket has been reserved?

USER: Helen Roberts.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Unfortunately we did not find any reservation on your given name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.