One of the interesting scenarios that you may come across in your time working with Azure is the transfer of resources from one Azure AD tenant to another. This however doesn't transfer the billing ownership of the resources. In such a case, changing billing ownership has to be performed.
The gotcha about this is that the subscription does not move with the RBAC roles that were assigned to it in the previous tenant but the resources are moved along with it. To overcome this, make sure that there is a security principal in the destination tenant that has the appropriate permissions to re-assign the RBAC roles.
To get started, we need to Understand the Architecture that is used in Azure to relate AD tenants - to -subscriptions -and to- resources.
At start of a new Azure AD tenant, there's a Management group. If this is enabled, It'll then become the Root management group. Multiple management groups can then be created that map to the root management group (child management groups) according to the Organization structure.
Now, an Azure AD tenant can exist without a subscription only in a scenario that you are using the Azure AD Free tier. If you are looking towards a higher tier such as Azure AD P1 or P2, these depend on a subscription hence one has to be created so that you can be billed for the extra features.
To get started, I will log into a tenant the contains the subscription that I want to move to a different/new tenant.
From there, I will browse to the subscription that I want move and then initiate the move to my new tenant/directory.
We should now be able to confirm our subscription in the new tenant. However you should note that sometimes this move could take up to an hour to propagate.
Eventually, we can confirm our move in the new directory.