Lease for existing tenants

[Greg Steinbrenner]

I just bought a duplex. The upper is vacant and there is a tenant in the lower unit on a month - to - month lease. The rent of the lower unit is below market. I plan to do some renovations in the upper unit before I get a tenant in it.  

My plan is to not rock the boat of the lower tenant before I get the upper fixed up and rented out.  At that point I would like to increase the rent of the lower unit and have a longer term lease.  

Any advice on how to handle the lease of the lower unit in the meantime?  Do I need to do anything before I ask for higher rent?  Does the current month-to-month agreement transfer to me?  

Thanks.