You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, can you help me with your name?

USER: Sure, my name is Thomas Jackson.

ASSISTANT: Please wait for a moment.

USER: Sure.

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

USER: Ok, that's fine. Thank you for your appreciable service.

ASSISTANT: Thank you for reaching us, have a nice day.