Not all Warlock Engineers can use magic, however, they may be upgraded to become a Level 1 or 2 Wizard. Upgraded Warlock Engineers use spells from the Skaven Spells of Ruin list. A Warlock Engineer can substitute one spell for Warp Lightning.
Source: Warhammer Fantasy: 7th Edition
Not all Warlock Engineers can use magic, however, they may be upgraded to become a Level 1 or 2 Wizard. Upgraded Warlock Engineers use spells from the Skaven Spells of Ruin list. A Warlock Engineer can substitute one spell for Warp Lightning.