...
To complete a full re-sync if you are using premium AAD to sync into myday you will first have to load the Azure portal and then follow the steps below.
Click on 'Enterprise Applications' on the left sidebar. If you do not have the option on the left sidebar, enter 'Enterprise Applications' in the search box and click on this in the search results.
...
3. Locate the application that was created for the azure sync.
...
6. Under the set ‘Provisioning Status’ click ‘Clear current state and restsrt restart Synchronisation’ box and set provisioning back to ‘On’.
...