Hi @Glenn Maxwell
We could change only the address of the site within the URL, for example:
https://contoso.sharepoint.com/sites/projectx
to https://contoso.sharepoint.com/sites/projecty
And once you change the address, you could use the new address until you change it again.
It can take about 10 minutes to change the site address (depending on the size of the site), and the site will be read-only during this time. We recommend changing addresses during times when site usage is low.
Note: If the Publishing feature is currently activated or was previously activated for the site, then changing the site address is unsupported.
You could refer to this article for more information:
https://learn.microsoft.com/en-us/sharepoint/change-site-address
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