You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Donna Wilson.

ASSISTANT: How can I help you?

USER: My tour trip was postponed, so I want to change an existing reservation. Could you help me in changing reservation?

ASSISTANT: Sure, I will help you in changing the reservation. Sorry to inform you that there is no reservation on your name.

USER: Not an issue.

ASSISTANT: Thank you for approaching us.

USER: Thanks for your good service.