You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Katherine Perez here. My holiday trip has been postponed, so I would like to change my existing reservation. Could you please help me in changing my existing reservation.

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Thank you for being patient. Unfortunately we found no reservation by your name.

USER: Ok, no issues. Thanks for your service.

ASSISTANT: Thank you for being with us.