You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, may I know your good name?

USER: I am Joseph Rodriguez.

ASSISTANT: How may I aid you Joseph Rodriguez?

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

ASSISTANT: Ok, please wait. I will update you once I found your reservation.

USER: OK.

ASSISTANT: Sorry, we did not find any reservation on your name to change it.

USER: Thank you for your response.

ASSISTANT: Thanks for connecting with us.