Calendaring updates.
 

I have a client that is using Outlook 2003 and Exchange 2003. She recently
sent out calendar updates their partner meetings. One of the recipients
declined the updates by accident. We resent the updates to that user only and
it cancelled the meeting on everyone else's calendar which created quite the
problem. What can we do in the future to prevent this from happening again?
Did we not send the update properly or what? Any help with this would be
greatly appreciated?