I usually keep my photos in folder by year then date. I imported a bunch into Lightroom into 2017 but which were not organised into folders due to me changing an import setting. If I look in the HDD they are all there under 2017 but not in date folders.
They are in there if I search for the image number but do not show up in the Navigator /Files list as they are not in folders.
As I have tweaked many of these I don't want to lose those tweaks but want to get them into folders by date. I can't import them as they are already there
I use LR 5 and they live on an external HD.
In the Library Module, right-click on the 2017 folder and choose "Create folder within 2017" from the context menu. Create the folder named the way you want it..Then (still in Lightroom) you can drag the misplaced photos into the new folder you just created. Be sure to drag by the image and not by the border.