welcome to fsc,
and it all depends on how it was done, how bad or how good the work was done, and how much you're interested in reversing it. a few examples below but you could probably hear a whole bunch of diff ways it could have been bagged. posting some pics may speed things up after you get a few more posts
for the front:
if you're lucky stock lca wasnt modified and the cup wasnt welded to it. you could probably get away with just a new drop spring and you may already have drop spindles. worst case for the front you may need a new lca if it was welded or replaced with an aftermarket arm.
for the rear same thing, if you're lucky all the stock brackets will still be there and youll need some leafs, worst case is a multi link with all the stock brackets gone and holes filled and you have no idea where the stock brackets would line up.... somewhere in the middle you may be able to use link setup with coil overs