You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I help you?

USER: I am Daniel Thompson, I want to change my existing reservation as my joining date got  rescheduled.

ASSISTANT: Ok, please stand by.

USER: Ok,.

ASSISTANT: Thank you for waiting, sorry no reservation found with your name.

USER: Ok no issues, thank you for the information.

ASSISTANT: Have a nice day.