We converted my son’s loft bed to a four post bed!
My son was tired of climbing the ladder to his loft bed so we lowered the mattress and removed the extra braces so that he can move the bed to the middle of the room if he likes. We saved all the extra pieces under the bed in case he ever wants the mattress raised higher.
Full plans for the loft bed and matching bunk bed can be found here: http://funwithwoodworkingstore.com/product-category/plans/