Rehabbing a tenant inhabited duplex

[Bryan Berrios]

I'm looking at a duplex that has been on the market for about half a year. I'm assuming it's been on so long because the pictures show it is highly outdated. Despite that, the listing says both sides are currently being rented out. My question is, how do you plan a rehab for a property that has tenants in it? An eviction? Do leases lose authority over new owners? If I were to buy this property, I would want to rehab the whole house and rent it for more than it's getting now. Any help is appreciated. 

[Carl Murray]

@Bryan Berrios

When the lease expires, raise the rent. If one leaves rehab the other and offer them the rehabbed side at the new rate. If they don’t want it raise their rent and rent the rehabbed side. If they leave, rehab that side and rent it.