You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I address you?

USER: I am Kenneth Anderson. Due to some emergency work, I want to change my existing reservation.

ASSISTANT: Ok. Please wait a while.

USER: Sure.

ASSISTANT: Thanks for being patient. Unfortunately, there is no reservation found by this name.

USER: Thank you.

ASSISTANT: Thank you for contacting us.