Swap a SharePoint online Site with another Site using “site swap” feature
SharePoint new experience pages are a great way to share ideas using images, documents, and web parts. You can create and publish pages quickly and easily, and they look great on any device. You can also make an existing page the home page(root) for your tenant.
Office 365 Notification MC187289 posted on August 5 tells us that Microsoft has started the roll-out of the SharePoint “site swap” feature described in Office 365 roadmap item 51259. The roll-out is slow and will complete in October 2019. The new feature uses the Invoke-SPOSiteSwap PowerShell cmdlet. The cmdlet swaps an entire site collection.
You will need Sharepoint Online powershell module installed.
Here is an example:
Invoke-SPOSiteSwap -SourceUrl https://contoso.sharepoint.com/sites/CommunicationSite -TargetUrl https://contoso.sharepoint.com -ArchiveUrl https://contoso.sharepoint.com/sites/Archive
https://blog.cloudadmin.me/wp-content/uploads/2019/09/image_thumb.png
This command will Archive 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.
Hope this helps.:)