You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Donna Nelson here.

ASSISTANT: How can I assist you Donna Nelson?

USER: Can you please help me out in changing my recent reservation? As my planned trip has been postponed.

ASSISTANT: Sure, I will help you with this. There is no active reservation found under your name in our database to change it.

USER: That's ok, thank you for giving the information.

ASSISTANT: Thank you for utilising our service.