Reattaching all photos in one shot

I'm dumbfounded. Can't figure out the right search verbiage, so here I am, asking what I'm sure is a question asked ad nauseam. Sorry.

What I need is simple. To reattach photos which are now in a different location without doing it one day at a time.

Obviously, I click on the exclamation point and it reattaches all the photos on same date in the that day's folder, but why isn't it attaching all the files in all dates? This makes no sense to me, and I'm sure there's a better way than reattaching six months of photos one day at a time.

First thought: Change where Lightroom PUTS the photos, which I gather is in the import dialogue, but these are already imported, so that doesn't help, or does it?

Logic would dictate that I could point Lightroom to the folder hierarchy in a matter of clicks and it'd repopulate. Just haven't figured out how. Please tell me it's easier than going day-by-day?

Thanks in advance and sorry for what's clearly an old question.