ALTER TABLE `helpdesk_handovers`
    ADD COLUMN `assigned_to`  INT UNSIGNED NULL DEFAULT NULL AFTER `updated_by`,
    ADD COLUMN `assigned_by`  INT UNSIGNED NULL DEFAULT NULL AFTER `assigned_to`,
    ADD COLUMN `assigned_at`  DATETIME     NULL DEFAULT NULL AFTER `assigned_by`,
    ADD COLUMN `due_date`     DATE         NULL DEFAULT NULL AFTER `assigned_at`,
    MODIFY COLUMN `status` VARCHAR(20) NOT NULL DEFAULT 'draft'
        COMMENT 'draft|in_progress|under_review|completed|archived';

ALTER TABLE `helpdesk_handovers`
    ADD INDEX `idx_assigned_to` (`tenant_id`, `assigned_to`);