You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hi. How may I address you?

USER: Donna Nelson here. Could you please help me in changing my existing reservation?

ASSISTANT: Sure, let me check the current status and revert you.

USER: Sure.

ASSISTANT: Thanks for waiting, we could not find any active reservation by the name you mentioned above in our data base.

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for approaching us.