Office 365: Error 500: Unable to convert regular mailbox to shared mailbox

Sometimes when you trying to convert Shared mailbox to Regular mailbox or vice versa on your Office 365 tenant you may face following error: (actually you may face the error when performing any type of mailbox conversions):

Error on proxy command 'Set-Mailbox -type: 'Shared' -Identity: 'your_alias' -Confirm:$False -Force:$True' to server Sever version 1941996320, Proxy method PSWS: Request return error with the following error message:
The remote server returned an error: (500)
Internal Servicer Error...
+CategoryInfo :NotSpecified: (:)
[Set-Mailbox], CmdletProxyException
+FullyQualifiedErrorID : Microsoft.Exchange.Configuration.CmdletProxyException,Microsoft.Exchange.Management.RecipientTasks.SetMailbox
+PSComputerName :

It seems to be internal Office 365 issue and there is no other solution other than give Microsoft a call, but in case you need convert mailboxes urgently, you may want to use following workaround:
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