Looking at inheriting tenants, how hard to terminate leases?

[Frank A.]

Hey Portland REIers,

My agent just sent me an amazing deal for a multifamily BUT I'd have to inherit tenants that are 70% undermarket rents. The property won't cash flow until I get the tenants out, rehab the units and lease tenants at market rents. How hard is it going to be to terminate the existing leases? What options do I have for a quick turn?

I'm still waiting to hear from a lawyer...but want to ask the hive mind first!! 

Thanks in advance!