You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: I am Joshua Taylor. My family tour trip got postponed, so I want to change an existing reservation. Could you please help me in changing the reservation?

ASSISTANT: Sure, Please wait a second.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for opting us.