Sharepoint Replace Root Site

Hello dandelly 

Did you try this from the GUI already and it did not work. then you might need to go through powershell to do this 

If you are using powershell.

First you need to connect to your SharePoint service by running this 

Connect-SPOService

url- https://teraberi-admin.sharepoint.com/ (your SharePoint admin center admin URL) 

and then run this

Invoke-SPOSiteSwap -SourceUrl https://contoso.sharepoint.com/sites/CommunicationSite -TargetUrl https://contoso.sharepoint.com -ArchiveUrl https://contoso.sharepoint.com/sites/Archive

what this does is this

Archives the existing site at https://contoso.sharepoint.com/ to https://contoso.sharepoint.com/sites/Archive and moves https://contoso.sharepoint.com/sites/CommunicationSite to https://contoso.sharepoint.com./ A site redirect will be created at https://contoso.sharepoint.com/sites/CommunicationSite that will redirect any requests to https://contoso.sharepoint.com./