Converting a user mailbox (paid license mailbox) to a shared mailbox in office 365 is pretty simple and straight forward. All of the existing mails and calendar settings are retained.
We can user New Exchange admin center to convert a mailbox to shared mailbox.
- Go to the Exchange admin center.
- Goto Recipients -> Mailboxes.
- Select the user mailbox in the mailbox list. Then select others option
- In other option, click on Convert to shared mailbox option.
- Simply click on Confirm and you are done.
- If the mailbox is smaller than 50 GB, you can remove the license from the user, and stop paying for it. Don’t delete the user’s account as it needs to be there as an anchor.