What hapens when something turns itself over?

Question

I ran into problems translating "The lorry turned over" Retourner usually takes avoir when it means invert, thus 'He turned over the lorry' = 'Il a retourné le camion, Il l'a retourné' -but would  'It (the lorry) turned (itself) over' = 'Il s'est retourné' or 'Il s'a retourné' ? Doesn't the first translation mean to put the lorry away, rather than leaving it in a ditch?

Accepted Answer

The truck turned over or rolled over, but it did it all by itself.  So, it's a reflexive verb.  "Il s'est retourné."  If someone were putting the truck away, it would be "Il a rangé le camion."  I don't think "retourner" means to return in English like returning an item to a store (rendre quelque chose au magasin pour un remboursement) or putting an item away.