A transforming robot is a robot that can change to take on the appearance or form of another object. This type of robot was a very popular toy concept in the 1980s; such toy robots could typically morph from a humanoid form to that of a vehicle, animal, or commonplace object. The transformation generally was by physically folding/bending/twisting and locking the robot's parts into the new shape, and it very rarely involved disassembling (physically separating) the parts and re-assembling them.
Transformers (Hasbro and Takara Tomy), a very popular franchise with two robot factions that fought against each other. The robots could transform into a wide range of things, like cars, trucks, planes, trains, motorcycles and robot animals.
Convertors (Select) featured the conflict between heroic and evil factions, in this case the heroic Defenders (and their Avarian allies) and the evil Maladroids (and their Insectors allies).