Howdy Patrick,
I would love to help you with this.
Before doing anything I would make a backup if I were you, just to be doubly safe. Tutorial: Making Backups.
I actually don’t see any reason why you can’t simply deactivate the plugin on your network, and uninstall it. Then install the zip from your site admin. This should not remove any data, but your backup will help you be extra sure. In fact, I think you will see all of your events just appear once you activate the plugin. You will need to reinput your license key, and double check all of your event settings to make sure they are still accurate. But in theory it should be pretty seamless.
Can you give that a go? Is it as seamless as I’m picturing?
Cheers!
– Brook