You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: My name is Helen Edwards and I want to change my reservation. Can you please help me?

ASSISTANT: Ok, I will check for the reservation you have asked in our reservation records.

USER: Ok.

ASSISTANT: Ok, the reservation you need is not available in our records.

USER: Thank you for the information.

ASSISTANT: Thank you for choosing our agency, have a great day.