You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be of your help?

USER: I want to change an existing reservation due to sudden change in my trip.

ASSISTANT: Sure, please provide your name.

USER: I am Stephiner Carter.

ASSISTANT: Give me sometime.

USER: Ok.

ASSISTANT: Thank you for waiting. Unfortunately there is no reservation found with your name.

USER: Thank you.

ASSISTANT: Thank you for consulting us.