If any mailbox items in your organization have the retention tag {0} applied, changing the retention ID will remove the tag ...

If any mailbox items in your organization have the retention tag {0} applied, changing the retention ID will remove the tag from those items. The items will inherit retention settings from tags on the parent folder or the default policy tag for the mailbox if such tags exist. If not, no move or delete actions will be enforced for those items. Do you want to continue?