Allow Upgrading and Downgrading of Building Blueprints

When trying to plan out complex sub-factories with a lot of pipes, belts, etc., I often find myself frustrated when I have some planned out, but decide I need to upgrade it. Or I want to downgrade parts of it that don't need to be a higher level to save materials. In order to accomplish that, one has to delete the belt / pipe and re-place it.
It should be possible in the entity menu to upgrade or downgrade it in-place, so long as it makes sense for that particular entity. This would greatly improve the planning experience, in my opinion.