As far as i know you can't convert them unless you take the back off and swap them round, removing and fitting is easy..remove the front grille by releasing the four clips on top and the same at the bottom between the grill and bumper (can't remember how many) then remove the grille...there are four bolts holding the headlight in..2 top and 2 bottom then just pull the light out,undo the multiplug on the back and replace/refit in reverse order.
As for the breather pipes, what makes you think they are blocked?.