How to Rehab a Fully Occupied Property?

[Shilpa Matlock]

I'm looking to buy a duplex, fully occupied at (drastically) under market rents in a small town. This is a long-distance, buy and hold investment. I want to rehab and raise rents. How can I do a rehab if there are already tenants in place? Do I have to wait for them to move out? What if they're long-term tenants, and they don't move for years to come? Or what if one unit vacates, can I rehab that side while the other side is still occupied? How do other investors handle this type of situation? I'm coming into this as a new investor, and any tips would be greatly appreciated, thanks!