Written by Thomas Speekenbrink
When you are moving your users from Exchange on-premise to Office 365 you will need to create a new Nebula Synchronizer Profile with the Office 365 connector.
First you have to login into my.nebulasynchronizer.com as admin user
Go to the Linked Users section
Click Action - Delete for each user
The calenders of the users needs to be cleaned in order to avoid duplicates. More info
Go to Profiles and create a new profile, use the o365 connector
Setup the Profile and link the users