You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Unfortunately, I would like to change my existing reservation can you please help me in this intent?

ASSISTANT: Sure, can you please tell the name on which the reservation is confirmed?

USER: Sure, I'm Donald Gonzalez here.

ASSISTANT: Please wait for a while to check your reservation status.

USER: Sure, I will wait take your time.

ASSISTANT: Sorry, there is no reservation found by your name.

USER: That's fine. Thank you for your service.

ASSISTANT: Thank you and have a nice day.