What happens when the surface ends at the laminar zone of the boundary layer?
Then you get a fully laminar boundary layer without transition. This can happen at very low Reynolds numbers, especially if no steep positive pressure gradients are encountered.

A steep pressure rise can lead to separation, and if the boundary layer does not change to a turbulent one, this separation can be final, with no re-attachment of the boundary layer. Then the attached flow ends before the body ends, but still the boundary layer is fully laminar.

It is not compulsory for transition to happen. If the flow is stable (either due to a negative, stabilising pressure gradient or due to very low Reynolds numbers), the boundary layer will stay laminar for its full length.