How to change the Recipient Type of a Mailbox in Exchange

get-mailbox "SomeName*" | ft name,RecipientTypeDetails

Name                         RecipientTypeDetails
----                         --------------------
SomeName - Denver            LegacyMailbox
SomeName - Houston           SharedMailbox
SomeName - Tulsa             SharedMailbox

get-mailbox "SomeName*" | set-mailbox -Type Regular

get-mailbox "SomeName*" | ft name,RecipientTypeDetails

Name                         RecipientTypeDetails
----                         --------------------
SomeName - Denver            UserMailbox
SomeName - Houston           UserMailbox
SomeName - Tulsa             UserMailbox