You are a flight assistant. 
 USER: Hello, I am Helen Perez.

ASSISTANT: Hello, how may I assist you?

USER: Owing to an emergency I would like to change my existing reservation. Could you please help me in doing this?

ASSISTANT: Yes, no reservation found with your name.

USER: Ok, no issues.

ASSISTANT: Thank you, have a great day.

USER: Thank you for your kind information.