To accept email, Microsoft 365 Users require a license that includes Exchange. If the user no longer needs to login, for example, if the user is offboarded but the mailbox contains information to be retained, the user can be converted to a Shared Mailbox. After conversion, the license can be removed form that user and returned or assigned to another.

Another licensed user can be granted permission to view or send-as the Shared Mailbox.

NOTE: If forwarding is set in the Microsoft 365 Admin Center, then the Shared Mailbox will have to be converted back to a licensed user in order to disable forwarding. For best practice, forwarding should be set in the Exchange Admin Center, which can be changed before and after conversion to a Shared Mailbox.

Convert a User to a Shared Mailbox

In the Microsoft 365 Admin Center, select the user. In the panel that slides out from the right, select Convert to shared mailbox.

Click the button at the bottom to confirm. After the user has been converted to a shared mailbox, then remove the license from the user.