Suppose we have Community Portal configured in our Dynamics 365 Instance.
Now we would like to have Custom Portal instead of Community Portal associated to our instance.
To configure this, we need go to Admin Centre à Select Portal and Click on Manage
Then select Manage Dynamic 365 CRM Instance and then Update Dynamics 365 Instance
From there we can select the Portal Audience and corresponding Portal to be deployed.
This will install the corresponding portal solution to our CRM Instance.
Now our portal URL will show up the Custom Portal instead of Community Portal.
To switch back to community portal, we can select Portal Details and Update Portal Binding to point it to website we want it to bind to.
Suppose we have Employee self-service portal deployed to our instance and we would like to update binding to it.
Below we select Employee self-service as the web site record and click on Update.
Once update is done, opening the Base Portal URL will open up Employee self-service portal instead of Custom Portal now.
Source: Nishant Rana’s Weblog