You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Jonathan Wilson.

ASSISTANT: How may I assist you today?

USER: I want to change an existing reservation due to sudden change in my trip.Can you help me?

ASSISTANT: Sure, please wait a moment.

USER: Thank you. Ok.

ASSISTANT: Sorry, there are no active reservations on your name to change.

USER: No issue, Thank you for the information.

ASSISTANT: Thank you for reaching our service.