Not offering a lease renewal. How should I do it?

[Juan Arroyo]

I am newbie in the real state investing world so any help is appreciated.

I bought a duplex in a working class neighborhood in Knoxville, TN. The duplex already had tenants but I want to update/remodel ONLY one unit to increase rent and to attract a family instead of two roommates.  The current lease does not mention anything about renewing the lease. Based on what I read, I should send them a letter stating that I will not renew the lease 30 to 60 days before the lease expiration date. 

Is there anything else I need to do? Also, you do have a letter/template that I can use?