Dragon's Suggestion. The steel dragon can innately cast the suggestion spell only requiring no components ( dc 15).

Multiattack. The dragon makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., 1 target. Hit: 14 (2d10 + 4) [piercing] damage. 

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 10 (2d6 + 4) [slashing] damage. 

Force Breath (Recharge 5-6). The dragon exhales a wave of force in a 30-foot cone. Each creature in that area must make a DC 15 constitution saving throw, taking 56 (16d6) force damage on a failed save, or half as much damage on a successful one.

Change Shape. The dragon magically polymorphs into a humanoid or beast that has a challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the dragon’s choice).

In a new form, the dragon retains its alignment, hit points, Hit Dice, ability to speak, proficiencies, Legendary Resistance, lair actions, and Intelligence, Wisdom, and Charisma scores, as well as this action. Its statistics and capabilities are otherwise replaced by those of the new form, except any class features or legendary actions of that form.