I have a SharePoint online site that I created years ago with my Microsoft account. When I created it I had a specific purpose in mind and so picked a subdomain that matched that purpose - e.g. https://subdomain.sharepoint.com . I quickly concluded that this had been an unwise approach - I would have been better picking a generic subdomain and then creating a subsite for my specific purpose. Now I am in a position where this is indeed causing me pain. I therefore wish to change my subdomain, and from then on I will create subsites as appropriate for specific purposes.
I have found instructions for how to change the subdomain of a site controlled by work or school accounts (you use a PowerShell extension - see https://learn.microsoft.com/en-us/sharepoint/change-your-sharepoint-domain-name), but that doesn't work with Microsoft accounts (I tried - it told me that I can't use a Microsoft account when I authenticated).
How do I do this for my personal SharePoint Online site?
