ALTER TABLE leads
    ADD COLUMN IF NOT EXISTS benefit_id VARCHAR(255) NULL,
    MODIFY COLUMN partner_id VARCHAR(255) NULL,
    ADD COLUMN IF NOT EXISTS assigned_to INT NULL,
    MODIFY COLUMN source VARCHAR(255) DEFAULT 'manual',
    MODIFY COLUMN notes TEXT NULL,
    MODIFY COLUMN status ENUM('new','contacted','qualified','converted','lost') DEFAULT 'new',
    MODIFY COLUMN name VARCHAR(255),
    MODIFY COLUMN email VARCHAR(255),
    MODIFY COLUMN phone VARCHAR(50),
    ADD COLUMN IF NOT EXISTS updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;