Literally swap them out. You can clone the data so you don't have to resync the blockchain but if you have a decent internet connection I'd just let it go redownloading everything from scratch
I have gigabit service to the house and I believe my initial sync took a few days. I can get the ssd for $89. The cloning device adds another $100 to the bill - and I only received my miner last month. I don't need to format or anything?