Convert AD synced office 365, to cloud only

install “Microsoft Online Services Sign in Assistant for IT Professionals”
Open Powershell (Admin)

Enter the following commands…

Install-Module MSOnline
Install-Module AzureAD
Import-Module AzureAD
Connect-MsolService
Get-msoluser (to test connection. Should list users)

NOTE:- Disable the Microsoft ADSync service!!

Enter the following commands…

Set-MsolDirSyncEnabled –EnableDirSync $false

get-msolcompanyinformation (to check if the sync is really gone ,it will say the sync status)

Clean up the users and groups (sbs etc)